Creating this Gluten-Free Chocolate Sheet Cake is easy if you follow these steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan.
2. Mix Dry Ingredients: In a large mixing bowl, sift together the gluten-free flour, sugar, cocoa powder, baking powder, baking soda, and salt.
3. Combine Wet Ingredients: In another bowl, whisk together the vegetable oil, buttermilk, eggs, and vanilla extract until well blended.
4. Combine Mixtures: Gradually add the wet ingredients to the dry ingredients, stirring until smooth and well incorporated.
5. Add Boiling Water: Carefully stir in the boiling water. The batter will be thin, but this is normal.
6. Pour Batter: Pour the batter into the prepared baking pan, smoothing out the top with a spatula.
7. Bake: Place in the preheated oven and bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.
8. Cool: Remove from the oven and allow the cake to cool in the pan for about 20 minutes before transferring it to a wire rack to cool completely.
9. Frost: Once the cake has cooled, spread the chocolate frosting evenly over the top.
10. Slice and Serve: Cut into squares to serve.

With these simple steps, you’ll have a delightful Gluten-Free Chocolate Sheet Cake ready to enjoy!