I've never had a Texas sheet cake, but I can't imagine not being happy with this cake. The cake itself is light and fluffy with a delicateness from the buttermilk and the frosting is chocolatey and rich. Add the crunch of toasted walnuts and this sheet cake is a little slice of heaven. I practically devoured this cake to be completely honest. Even though this recipe makes a huge cake, the fact it's thin makes the cake to frosting ratio perfect.
It's important to note that the frosting needs to be added to the cake while it's still hot. This gives the frosting a fudgy quality. Very good. Also, make sure your sheet pan is 18×13. Otherwise you'll have a huge mess on your hands. I only had half a stick of butter left over so I had to use some shortening in the frosting to make up for it. Turned out great though.
Would I make this again? Oh yes! Perfect for summer entertaining. I plan on making it for our next bbq.
Chocolate Sheet Cake
2 cups Flour
2 cups Sugar
1/4 teaspoons Salt
4 Tablespoons (heaping) Cocoa
2 sticks Butter
1 cup Boiling Water
1/2 cups Buttermilk
2 whole Beaten Eggs
1 teaspoon Baking Soda
1 teaspoon Vanilla
8 tablespoons butter (one stick)
1/2 cup heavy cream
1/2 cup dutch-process cocoa powder
1 tablespoon corn syrup
3 cup powdered sugar
1 tablespoon vanilla
1 cup toasted pecans, chopped
1. In a mixing bowl, combine flour, sugar, and salt. In a saucepan, melt butter. Add cocoa. Stir together. Add boiling water, allow mixture to boil for 30 seconds, then turn off heat. Pour over flour mixture, and stir lightly to cool.
2. In a measuring cup, pour the buttermilk and add beaten eggs, baking soda, and vanilla. Stir buttermilk mixture into butter/chocolate mixture. Pour into sheet cake pan and bake at 350-degrees for 20 minutes.
3. For the icing: About 5 minutes before the cake is done, heat the butter, cream, cocoa, and corn syrup in a large saucepan over medium heat, stirring occasionally, until smooth. Off the heat, whisk in the powdered sugar and vanilla. Spread the warm icing evenly over the hot cake and sprinkle with the pecans.
4. Let the cake cool to room temperature on the wire rack, about one hour, then refrigerate until the icing is set, about one hour longer. Cut into 3″ squares. Serve. Cake can be wrapped in plastic and refrigerated for 2 days. Return to room temperature before serving
Source: Adapted from the Pioneer Woman and America's Test Kitchen