Gluten-Free Texas Sheet Cake

1 . Stage

Preheat the oven to 350 degrees F (175 degrees C). Grease an 18x13x1-inch baking pan with cooking spray.

2 . Stage

Make the cake: Combine butter, water, and cocoa powder in a saucepan over medium heat. Stir together and bring to a boil. Remove from the heat and mix in sugar and vanilla extract. Set aside and allow to cool for about 15 minutes.

3 . Stage

Whisk together buttermilk and eggs in a small bowl. Combine gluten-free flour, baking soda, and salt in a large bowl, mixing well; stir in buttermilk mixture, then stir in cooled cocoa mixture. Stir batter well until no lumps remain. Pour into the prepared pan.

4 . Stage

Bake in the preheated oven until a toothpick inserted in the center comes out clean and the cake is starting to pull from the sides of the pan, 25 to 35 minutes. Let cool for 15 minutes before frosting.

5 . Stage

While the cake is cooling, make the frosting: Bring butter, cocoa powder, and milk to a boil in a saucepan over medium heat. Remove from the heat once milk is boiling; whisk in confectioners' sugar and vanilla. Pour frosting over the warm cake and spread evenly over the top and sides with a spatula. Sprinkle with chopped pecans.

6 . Stage

Allow cake and frosting to cool completely before serving, about 30 minutes.