Preheat your oven to 325°F. Grease and line an 8-inch x 8-inch (for thicker bars) or 9-inch x 9-inch (for thinner bars) baking pan, and set it aside.
Make the blondies.
In a large bowl, place the flour blend, xanthan gum, cornstarch, salt, and baking soda, and whisk to combine well. Set the mixture aside.
In a small, heavy-bottom saucepan, place the butter and granulated sugar. Melt over low heat, whisking frequently, until smooth.
Remove the pan from the heat, and add the brown sugar. Whisk to combine and to melt the brown sugar until smooth. Set the saucepan aside to cool briefly.
In a large mixing bowl, place the eggs and vanilla and beat with a handheld mixer or whisk with a large balloon whisk until foamy.
While whisking or beating constantly, add the butter and sugars mixture. Continue whisking or beating until very smooth.
Add the dry ingredients, and mix by hand until well-combined. The batter will be very sticky, and very soft and pourable.
Add most of the chips, and mix until evenly distributed throughout the batter.
Pour the batter into the prepared baking pan, and shake it into an even layer. Bang the pan flat on the countertop to break any large air bubbles in the batter.
Sprinkle the remaining chips evenly on top of the batter. Bang the pan again a few times to help the chips adhere.
Place the pan in the center of the preheated oven and bake until a toothpick inserted in the center comes out nearly clean, with just a few moist crumbs attached (about 40 minutes for the 9-inch x 9-inch pan, and about 50 minutes for the 8-inch x 8-inch pan).
Remove the pan from the oven, place the pan on a wire rack and allow the bars to cool in the pan until stable enough to move without cracking (at least 20 minutes).
Remove the bars from the pan, place on the wire rack and allow to cool completely before slicing into 9 equal pieces.
Make the optional maple butter
In a medium-size, heavy-bottom saucepan, place the chopped butter. Melt the butter over medium-low heat. Reduce the heat to low, add the brown sugar, and stir until the mixture is wet and grainy.
Add the maple syrup and continue to cook over low heat, stirring occasionally, until the mixture begins to look smooth (about 3 minutes).
Add the heavy whipping cream and switch to a whisk. Cook, whisking constantly, until the mixture is smooth (about 1 minute).
Bring the mixture to a simmer and continue to cook, whisking occasionally, for about another 5 minutes, or until it is slightly reduced and coats the back of a spoon.
Remove from the heat, and taste the maple butter with a clean spoon. Add pure vanilla extract and coarse salt to taste.
To serve
Place each blondie on a separate plate, drizzle with some warm maple butter sauce, top with a scoop of vanilla ice cream, and drizzle with more sauce. Moderation is not really the point here.
Notes
For the chips You can use any sort of stable mix-ins that you like. If you’re using white chocolate and butterscotch chips, like I do mostly, read labels carefully to ensure that everything you’re using is safly gluten free.If you like nuts in your blondies, I recommend replacing half of the chips with chopped raw pecans. You can also use walnuts, or any other nut that is tender when raw.For the maple butter sauceThe maple butter can be made a few days ahead of time. Store it in a sealed container in the refrigerator. It will solidify.When you’re ready to serve the sauce, uncover it and warm it in the microwave or in a water bath in a small saucepan on the stovetop over medium heat, stirring frequently until smooth. Originally published on the blog in 2014. In 2021, recipe tweaked slightly, video, text, and some photos new; in 2022, new text resources added.