Gluten-free Texas Sheet Cake

• Preheat your oven to 350F (176C). Line a large rimmed baking sheet with unbleached parchment paper and set it aside.

First, make the cookie dough

• In a medium-sized, heat safe bowl, place the chopped butter and chocolate, and melt in the microwave in 45-second bursts at 60% power until melted and smooth or over a double boiler on the stovetop. To the melted chocolate mixture, add the sugar and mix to combine, then the egg and vanilla, mixing to combine after each addition. Set the mixture aside. In a large bowl, place the flour, xanthan gum, salt, cinnamon, cocoa powder and baking soda, and whisk to combine well. Create a well in the center of the dry ingredients, and pour in the wet chocolate mixture. Mix until the dough comes together. It will be thick but soft.

Shape and bake the cookies

• Divide the dough into 24 portions, each about 1 tablespoon, and roll each into a ball between your palms. Press the dough into disks about 1/2-inch thick, and place about 1-inch apart from one another on the prepared baking sheet. Place the baking sheet in the center of the preheated oven and bake until just set in the center, about 8 minutes. Remove the cookies from the oven and allow to cool for 5 minutes on the baking sheet or until set before transferring to a wire rack to cool completely. If you attempt to move them right after they come out of the oven, they will break.

Make the icing and ice the cookies

• In a large bowl, place the confectioners’ sugar, cocoa powder and salt, and whisk to combine well. Create a well in the center of the sugar mixture and pour in the melted butter, milk and vanilla, mixing constantly until well-combined. Place the wire rack of cookies over a large piece of parchment paper to catch drips. Spoon the icing over the cooled cookies on the wire rack, and spread gently to coax the icing toward the edges of the cookies so it drips down the sides and through the rack. Allow the cookies to sit at room temperature until completely set. The icing will harden so it is dry to the touch, but will still give when pressed on firmly.

Make-Ahead Instructions

• Freeze un-iced cookies in a single layer before placing in freezer-safe wrap and storing. Defrost cookies, ice according to the recipe instructions, and allow to set before serving.