1-Preheat your oven to 350°F (175°C) and grease an 18×13 inch sheet pan to prevent sticking.

2-In a medium saucepan over medium heat, combine 1 cup water, 1 cup butter (227 g), and 3 tablespoons cocoa powder (22.5 g). Bring this mixture to a boil, then remove from heat.

3-In a separate bowl, whisk together 2 cups flour (240 g), 2 cups sugar (400 g), 1 teaspoon baking soda (5 g), and 1/2 teaspoon salt (2.5 g) until well mixed.

4-In another bowl, whisk together 1/2 cup sour cream (120 g), 2 eggs, and 1 teaspoon vanilla extract (5 ml). Add this to the dry ingredients and mix until just combined.

5-Pour the hot chocolate mixture from the saucepan into the batter. Stir until smooth and free of lumps, then pour evenly into the prepared pan and smooth the top.

6-Bake for 15-20 minutes, or until the cake is set typically around 15 minutes due to the thin pan.

7-While the cake bakes, make the frosting: In a saucepan, combine 6 tablespoons milk (90 ml), 3 tablespoons cocoa powder (22.5 g), and 1/2 cup butter (115 g). Bring to a boil.

8-Remove the frosting from heat and stir in 3 3/4 cups powdered sugar (450 g), beating until smooth.

9-Immediately pour the hot frosting over the hot cake as soon as it comes out of the oven, then spread it evenly with a spatula.

10-Let the frosting set for about 10 minutes before serving. Enjoy your fresh Texas Sheet Cake at room temperature.