10 tablespoons (140 g) unsalted butter, chopped
3 ounces bittersweet chocolate, chopped
1 3/4 cup (245 g) basic xanthan gum-free gluten free flour (162 grams superfine white rice flour + 54 grams potato starch + 29 grams tapioca starch/flour)
3/4 cup (60 g) natural cocoa powder
1/2 teaspoon baking soda
1/2 teaspoon kosher salt
1 1/8 cups (225 g) granulated sugar
1 large egg white (25 g), at room temperature
3 ounces miniature chocolate chips (optional)
Preheat your oven to 325°F. Line a large rimmed 13-inch x 18-inch (half-sheet) pan with unbleached parchment paper or greased or nonstick aluminum foil, and set it aside.
In a small, heat-proof bowl, place the butter and chopped chocolate, and melt them in the microwave in 30-second bursts or over a double boiler until smooth. Remove from the heat and set aside to cool briefly.
In a large bowl, place the flour blend, cocoa powder, baking soda, salt, and sugar, and whisk to combine well. Create a well in the center of the dry ingredients, add the chocolate and butter mixture, and the egg white, and mix to combine. The mixture will be thick and somewhat crumbly. Add the (optional) miniature chocolate chips, and mix until they are evenly distributed throughout the cookie dough.
Transfer the mixture to the prepared baking sheet, and spread into an even layer. Place another sheet of parchment paper on top of the batter in the baking sheet, and top with another half sheet pan. Press down evenly on the top sheet pan to press the batter into an even, compressed layer. Remove the top baking sheet and parchment paper, and place in the center of the preheated oven. Bake for about 20 minutes, or until the brownies are mostly firm to the touch. Remove the pan from the oven and allow the brownies to cool completely in the pan. They will crisp as they cool.
Once the brownies are completely cool, break them into irregular pieces. Store at room temperature in an airtight glass container to retain crispness.
Originally published on the blog in 2013. Recipe unchanged, most photos, video and text new.