Texas Sheet Cake

Preheat the Oven: Begin by setting the oven to 375°F (190°C). This temperature is ideal for baking cakes, providing enough heat to rise and set the structure without burning the edges.
Combine Margarine, Water, and Cocoa: In a large saucepan, combine 1 cup of margarine with 1 cup of water and bring to a boil. Add 4 tablespoons of cocoa powder to the mixture, stirring until well incorporated. This process will melt the margarine and dissolve the cocoa, creating a smooth chocolate base for your cake.
Cool the Mixture: Remove the saucepan from the heat and allow the chocolate mixture to cool slightly, ensuring that it does not cook the eggs upon their addition.
Add Remaining Cake Ingredients: To the slightly cooled chocolate mixture, add 2 cups of all-purpose flour, 2 slightly beaten large eggs, 1 teaspoon of baking soda, 2 cups of granulated sugar, and ½ cup of sour cream. Mix these ingredients thoroughly until the batter is smooth and uniform. The sour cream will help tenderize the cake, while the baking soda acts as a leavening agent, giving the cake a light and fluffy texture.
Bake the Cake: Pour the cake batter into a buttered and floured 10”x15”x2" baking pan. Place the pan in the preheated oven and bake for 22 minutes, or until a toothpick inserted into the center comes out clean. The cake should be springy to the touch and pull away slightly from the edges of the pan.

Prepare the Frosting: While the cake is baking, prepare the frosting. In a separate saucepan, bring ½ cup of margarine and 6 tablespoons of milk to a boil. Add 4 tablespoons of cocoa powder and stir until the mixture is smooth.
Finish the Frosting: Remove the saucepan from heat and incorporate 1 cup of chopped walnuts, 3 ½ cups of powdered sugar, and 1 teaspoon of vanilla extract into the cocoa mixture. Beat the frosting until smooth and creamy, ensuring that all ingredients are well combined and free of lumps.
Frost the Cake: Once the cake is removed from the oven and while it is still warm, pour the prepared frosting over the top. Spread the frosting evenly, using a spatula to cover the entire surface. The warmth of the cake will help the frosting slightly melt into the top layer, creating a rich and gooey texture.
Cool and Serve: Allow the cake to cool in the pan on a wire rack until the frosting is set. This resting period allows the flavors to meld and the frosting to firm up, making it easier to slice. Once cooled, cut the cake into squares and serve.