Step 1: Prepare the Pan

Preheat oven to 350°F (175°C). Grease and flour a 10×15 inch sheet pan. This size gives the cake its signature thin, melt-in-your-mouth structure.

Step 2: Make the Batter

In a large bowl, combine:

• 2 cups all-purpose flour

• 2 cups white sugar

• 1 teaspoon baking soda

• ½ teaspoon salt

Beat in:

• ½ cup sour cream

• 2 eggs

Set this mixture aside while you prep the chocolate base.

In a small saucepan, melt:

• 1 cup butter

Then stir in:

• 1 cup water

• 5 tablespoons cocoa powder

Bring to a gentle boil, then remove from heat. Let cool slightly, then stir this cocoa mixture into the egg-flour mixture. Mix until blended. The batter will be rich, chocolatey, and slightly loose—just the way we want it.

Step 3: Bake the Cake

Pour the batter into your prepared 10×15 inch pan. Bake for 20 minutes, or until a toothpick inserted into the center comes out clean.

🔔 Pro Tip: While the cake is baking, prep your icing. It’s important to frost the cake while it’s still warm—that’s how you get the gooey, slightly sunken texture that makes Texas Sheet Cake so addictive.

🍫 Step 4: Make the Icing

In a large saucepan, combine:

• 6 tablespoons milk

• 5 tablespoons unsweetened cocoa powder

• ½ cup butter

Bring to a boil, then remove from heat and stir in:

• 4 cups confectioners’ sugar

• 1 teaspoon vanilla extract

Fold in:

• 1 cup chopped walnuts (optional)

Stir until smooth and well-blended.

🍯 Frosting Tip: You want the icing to be pourable and warm—but not overly hot—when spreading. Pour it gently over the warm cake and let it spread naturally. Use a spatula only if needed.