Easy Gluten Free Texas Sheet Cake

This rich, fudgy gluten free chocolate sheet cake is a simple one-bowl chocolate cake recipe with an easy, poured icing. It's just the best ever cake for a potluck or birthday.

Why this is the best gluten free chocolate sheet cake recipe

This is a moist gluten free chocolate sheet cake that's rich, but still light enough to enjoy after a big meal, or after a light brunch. It's very easy to make with simple ingredients you probably already have on hand, as long as you're ready to go with one of our all purpose gluten free flour blends.

There's no melted chocolate in the batter, and in fact there isn't even a ton of unsweetened cocoa powder. That's why the cake pairs so well with a poured chocolate icing, and together they stay incredibly moist, with just the right amount of chocolate flavor to please chocolate and vanilla lovers alike!

The cake batter is relatively thin, which is common in sheet cakes that aren't designed to bake up thick, or tall. The extra moisture in a cake like this with a thin batter evaporates in the oven since so much of the batter is exposed to the heat early on in the baking process. And all that moisture also ensures a super tender cake crumb.

Is this a Texas sheet cake?

When I first published this recipe in 2012, it was adapted from a recipe (linked in the instructions below) for Texas sheet cake. I didn't grow up eating that sort of cake, but readers kept asking for a gluten free chocolate sheet cake recipe (of the Texas variety, they said!) so I did some research.

Back then, to me, a “sheet cake” was a thick, bakery-style layer cake that was loaded with that amazingly delicious, who-knows-what's-in-it, sugar-rush-style white frosting. A Texas sheet cake, it turned out was a thin cake baked in a jelly roll-style rimmed baking sheet with a poured icing. After the first try, I was in ❤.

I guess this is technically a Texas sheet cake, still. But if I don't call it that, I don't have to worry about being told that I've done something nontraditional like sprinkling the hot poured icing with pretty nonpareils.

A thin sheet cake like this one is so perfect for any sort of gathering, for a birthday or just a potluck. You know how adults often say, “I'll just have a little slice”? Well, there's no cake easier to customize in the size of slices than a thin sheet cake. And then when my youngest comes along and asks for the “biggest slice,” you can accommodate her too!

If you're hoping for a different sort of chocolate cake, here is my most classic gluten free chocolate cake recipe. And of course, if you're more of a vanilla-type person, there's always the very best gluten free vanilla cake.

Gluten free chocolate sheet cake ingredient notes

• Gluten free flour – I like to use Better Batter gluten free flour (always the classic blend) in this recipe for its perfect balance of ingredients, including xanthan gum and superfinely ground rice flour.
• Unsweetened cocoa powder – You can make this cake with either natural or Dutch-processed unsweetened cocoa powder. Dutch-processed cocoa powder is less acidic and has a more rich chocolate flavor, so I prefer that if possible.
• Granulated sugar – The sugar in the cake, of course, adds sweetness, but it also helps tenderize the cake significantly. I recommend against reducing the amount, which is a question I get a lot, since your cake with be less tender.
• Baking soda – The baking soda here adds rise, and will also neutralize the acid in natural unsweetened cocoa powder, if you're using that instead of Dutch-processed.
• Salt – Salt balances the sweetness and brings out the chocolate flavors.
• Butter – Adding buttery flavor, moisture, and tenderness from the fat, unsalted butter is an essential ingredient in this moist and tender chocolate sheet cake.
• Coffee – You don't taste any coffee flavor when you add the brewed coffee to this cake. It really just helps enhance the chocolate flavor without the need to add more melted chocolate or even more cocoa powder.
• Sour cream – The acid in sour cream tenderizes the crumb, and of course adds moisture. If you don't have sour cream, you can use an equal amount of plain Greek-style yogurt.
• Egg and egg yolk – The egg adds rise and some richness, and the extra egg yolks is there for added richness.
• Vanilla extract – Pure vanilla extract enhances the chocolate flavor and adds depth.

How to make this gluten free (Texas) sheet cake

Choose the right pan

I think the secret to making a sheet cake ultra rich and moist like this one, is to make it no more than one-inch thick in a jelly roll-style rimmed baking sheet. If you were to use this recipe and double it, then bake it in a 9 x 13-inch baking pan, the slices would likely fall apart as you tried to remove them from the pan.

Here, the pourable batter is made in one bowl, with melted butter, then smoothed out in a rimmed baking sheet. It's baked just until the cake springs back when pressed gently.

It can be a bit challenging to spread the batter into a perfectly even layer in the pan, but not to worry. The poured icing covers all inconsistencies.

Monitor your gf chocolate cake's baking time

Be sure not to overbake this cake, or you'll sacrifice that extra-tender crumb. It's the kind you pick up with the tines of your fork and they smoosh a little when you're grabbing them.

Bake the cake just until the cake springs back when pressed gently toward the center. Don't bother with the toothpick test for doneness, since it isn't always accurate here.

Icing your sheet cake

Ideally, you'll pour the hot icing on a freshly-baked cake that's still warm from the oven, and work to spread out the icing quickly before it begins to set. The icing doesn’t harden, even when chilled, but it will set and wrinkle if you try to disturb it as it cools. The icing will likely have a few bubbles and lumps. They’ll even out as the cake cools, though.

How to make a smaller cake

When I originally published this recipe, the cake was made smaller and baked in a quarter sheet pan that measures 9 x 13 x 1-inch. Despite the relative suggestion of the names of the pans, a standard quarter sheet pan doesn’t have half the capacity of a half sheet pan.

If you’d like to make this cake in a quarter sheet pan, you’ll need to reduce the recipe by one-third. The easiest way to do that is to multiply each ingredient by 2/3. That’s a simple reduction for most ingredients, but requires some alterations for others.

For ease, here are the ingredient amounts for baking this chocolate cake in a quarter sheet pan (9 x 13 x 1-inch). Just follow the instructions below for the method, changing only the pan size. The baking time should be roughly the same:

• For 2/3 of the cake, use these ingredients in place of those listed in the recipe card below, but using the same method:
  • 1 cup (140 g) all purpose gluten free flour blend
  • 1/2 teaspoon xanthan gum (omit if your blend already contains it)
  • 3 tablespoons (15 g) unsweetened cocoa powder
  • 1 cup (200 g) granulated sugar
  • 1/2 teaspoon baking soda
  • 1/4 teaspoon kosher salt
  • 8 tablespoons (112 g) unsalted butter, melted
  • 1/2 cup (4 fluid ounces) brewed coffee, at room temperature
  • 1/2 cup (112 g) sour cream or plain Greek yogurt, at room temperature
  • 1 egg (50 g, weighed out of shell) at room temperature, beaten
  • 3/4 teaspoon pure vanilla extract
• For 2/3 of the icing: use these ingredients in place of those listed in the recipe card below, but using the same method:
  • 2 cups (230 g) confectioners’ sugar
  • 3 tablespoons (15 g) unsweetened cocoa powder
  • 1/8 teaspoon kosher salt
  • 8 tablespoons (112 g) unsalted butter, chopped
  • 3/8 cup (3 fluid ounces) milk, any kind
  • 1 teaspoon pure vanilla extract
  • nonpareils, for sprinkling (optional)

How to make an awesome gluten free chocolate frosting

Frosting ingredient notes

• Confectioners' sugar – Confectioners' sugar, which is powdered sugar with an added starch or other anti-caking agent, provides sweetness and structure to the chocolate frosting.
• Unsweetened cocoa powder – The chocolate flavor comes entirely from cocoa powder here. Dutch-processed cocoa powder will add richer, deeper chocolate flavor, but natural cocoa powder works, too.
• Salt – Salt brightens the flavor of the frosting, and balances the sweetness.
• Butter – Melted butter adds buttery flavor and perfect texture as it cools; the butter is what makes gives the top of your frosting that beautiful crackly sheen when it sets.
• Milk – Just a touch of milk makes the frosting pourable and keeps it relatively soft even after it sets.
• Vanilla extract – Pure vanilla extract enhances the chocolate flavor and adds depth.
• Nonpareils for sprinkling (optional) – Gluten free nonpareils are just for fun and entirely your choice, of course! Add them when the frosting is first poured, or they won't adhere.

Making the sheet cake frosting

Traditionally, the frosting is made as the cake is nearing the end of its baking time, so it's ready the moment the cake comes out of the oven. It's poured over the hot cake, and they cool and set together.

If you want to ensure a smoother frosting, sift your confectioners' sugar and cocoa powder into a mixing bowl before you melt the butter and heat the milk. Whisk the melted butter into the sifted dry ingredients, and pour it over the hot cake.

Storage instructions

If you plan to make the cake more than a couple of hours before serving it, I would recommend storing the cake unfrosted. I know it goes against the recipe instructions, which call for pouring the hot frosting over the just-baked cake, but the cake simply doesn't store as well once it's been frosted.

If you want to make the cake ahead of time, let it cool in the pan, unfrosted, then cover the pan and store it in the freezer. Defrost fully at room temperature, then add the frosting and allow it to set.

If you have leftover frosted cake, slice the leftover cake into rectangular portions and store them in a flat, well-sealed container in a single layer in the refrigerator. The frosting will keep the cake moist for at least 3 days as long as the container has a tight-fitting lid.

Ingredient substitutions

Dairy free

When I recently decided to make this cake again, thinking it would be perfect for the long holiday weekend coming up in the U.S., the first thing I did was make sure it worked with dairy-free substitutes. And I'm happy to report that it works perfectly!

In place of butter in the cake itself, I used half virgin coconut oil and half nonhydrogenated vegetable shortening (I use Spectrum brand). Both measurements are by weight.

In place of the sour cream or Greek yogurt, I used a plain, unsweetened nondairy yogurt. Since the yogurt I used wasn't thick enough, I strained it until it was the consistency of Greek yogurt, and then measured the proper amount by weight. For milk, I used unsweetened almond milk.

In the icing, I recommend using all virgin coconut oil in place of the butter. Shortening has almost no moisture, and the icing has a tendency to seize up and end up too thick to spread.

Egg free

I haven't tried making this recipe egg-free. The one egg could most likely be replaced by a “chia egg” (1 tablespoon ground chia seeds + 1 tablespoon lukewarm water, mixed and allowed to gel), and the egg yolk by another tablespoon of virgin coconut oil, melted.

For a naturally egg-free and dairy-free cake, try my crazy cake gluten free chocolate cake. You won't believe how moist it still is!

Sugar free

I haven't tried making this cake with sugar alternatives, but I'm anxious to try. I'd recommend trying Lankato brand monkfruit granulated sugar substitute in place of the granulated sugar, by weight.

Watch the consistency of the cake batter, though. If it seems too thick, as sugar substitutes tend to be drying in baking, add more brewed coffee by the teaspoonful until it seems similar to the texture you see in the video.

In place of the confectioners' sugar, Swerve has a confectioners' sugar-style replacement that should work. Again, watch the consistency and add more liquid as seems necessary.

Brewed coffee

Since the only chocolate in this recipe comes from cocoa powder, without any melted chocolate, the brewed coffee really helps to deepen the flavor. Caffeine isn't at all necessary, though, so brewed decaffeinated coffee is just fine. You can replace the coffee with water, but you'll sacrifice flavor.

FAQs

What's the difference between a gluten free sheet cake and a regular cake?

A sheet cake is baked in a rectangular pan, and is typically not as deep as a “regular” cake. It's also not usually made as a layer cake, although you can make a layered sheet cake.

What makes a gf Texas sheet cake different?

They say that a Texas sheet cake is so-called because it's the size of Texas, but I don't know if that's true or not! This cake is different because it's made in a jelly roll or other sheet pan in a thin layer, and has a hot boiled butter icing on top.

Can I use this gluten free sheet cake recipe to make cupcakes?

No, I would not try to use this recipe to make cupcakes, since the batter is formulated to bake up short, like in a jelly roll pan, not tall, like in a cupcake. I would use our recipe for the perfect gluten free chocolate cupcakes instead.

Why didn't my cake rise?

If your cake didn't rise properly, check to see if your baking soda is out of date. If your chemical leavener is not fresh, it won't activate. Since there's only baking soda which activates the moment you add liquid to it, and no double-acting baking powder, if you mix the batter and don't put it right in the oven, your baking soda may not have lasted long enough to provide a rise in the oven.

Why is my cake rubbery?

If your cake came out rubbery, it may have risen and then fallen as it cooled, resulting in a gummy, dense cake without a real crumb. That's usually due to a too-hot oven that baked the outside too fast, before the inside has a chance to bake all the way to the center. It also can happen if you overmeasure your liquid or undermeasure your flour, both of which can lead to a cake with more moisture than can bake out in the oven.