Gluten Free Chocolate 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.

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 are 10 gluten free chocolate cake recipes for everything you can imagine. My favorite is probably the classic one bowl gluten free chocolate cake. And of course, if you’re more of a vanilla-type person, there’s always the very best gluten free vanilla cake.

How to make a gluten free chocolate sheet cake

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.

Be sure to pour the hot icing on the hot cake, and work 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 sheet cake

When I originally published this recipe, the cake was made smaller and baked in a quarter sheet pan which 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: 1 cup (140 g) all purpose gluten free flour; 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 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: 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)

Ingredients and 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.

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.

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Gluten Free Chocolate Sheet Cake

Sample rating item

Prep time: 10 minutes

Cook time: >20 minutes

Yield: 1 half sheet cake

Ingredients

For the cake
1 1/2 cups (210 g) all purpose gluten free flour (I used Better Batter)

3/4 teaspoon xanthan gum (omit if your blend already contains it)

5 tablespoons (25 g) unsweetened cocoa powder (natural or Dutch-processed)

1 1/2 cups (300 g) granulated sugar

3/4 teaspoon baking soda

1/4 teaspoon kosher salt

12 tablespoons (168 g) unsalted butter, melted

3/4 cup (6 fluid ounces) brewed coffee, at room temperature

3/4 cup (168 g) sour cream or Greek yogurt, at room temperature

1 egg (50 g, weighed out of shell) + 1 egg yolk, at room temperature, beaten

1 teaspoon pure vanilla extract

For the icing
3 cups (345 g) confectioners’ sugar

5 tablespoons (25 g) unsweetened cocoa powder (Dutch-processed, if possible)

1/4 teaspoon kosher salt

12 tablespoons (168 g) unsalted butter, chopped

1/4 cup + 3 tablespoons (3 1/2 fluid ounces) milk, any kind

1 teaspoon pure vanilla extract

Nonpareils, for sprinkling (optional)

Instructions

• Preheat your oven to 325° F. Line a half sheet pan (13 x 18 x 1 inches) with unbleached parchment paper and set it aside.

• In a large bowl, place the flour, xanthan gum, cocoa powder, sugar, baking soda and salt, and whisk to combine well. Set the bowl aside. Pour the melted butter, coffee, sour cream, egg and vanilla, and mix until just combined. Pour the batter into the prepared sheet pan, and spread into an even layer with a wet spatula. Place the baking sheet into the preheated oven and bake until the cake is uniform in color and springs back readily when pressed gently with a finger, about 20 minutes.

• During the last 10 minutes of the cake’s baking, make the icing. In a large bowl, place the confectioners’ sugar, cocoa powder and salt and whisk to combine well. Set the bowl aside. In a clean small saucepan, place the butter and the milk, and cook over medium heat, stirring occasionally, until the butter is completely melted. Remove the saucepan from the stove, pour the hot butter and milk mixture over the dry ingredients, add the vanilla, and mix to combine.

• Ice the cake. As soon as the cake is finished baking, remove the pan from the oven and pour the hot icing over the hot cake. Working quickly to ensure that the icing is spread before it sets, with an offset spatula or butter knife, spread the icing over the entire surface of the cake. Sprinkle immediately with the (optional) nonpareils. Allow the cake to cool completely in the pan to room temperature. For easier slicing, chill the cake, then lift it out of the pan by the parchment paper. Slice it into 12 to 16 generous pieces, and serve chilled or at room temperature.

• Adapted from The Spruce Eats. Originally published as Gluten Free Texas Sheet Cake on the blog in 2012 (!). Recipe scaled up 150% and baked in a half, rather than a quarter, sheet pan, photos and video new.