I have tried this Texas Sheet cake and like it very much.

White Texas Sheet cake
10x15x1 inch cake
Preheat 375

1 cup soft butter 1 teaspoon baking soda
1 cup water 2 cups all-purpose flour
2 cups white sugar 2 eggs
1 teaspoon almond/vanilla extract
1/2 cup sour cream

In large saucepan, bring 1 cup butter and the water to boil. Remove from heat, and stir in sugar, flour, eggs, sour cream,extract( whatever you like) and baking soda. Stir till smoooth. Pour batter into a greased 10x15x1 inch baking pan that is greased and floured. bake 375 degrees for 20 to 22 minutes or until cake is golden. Test done, Cool 20 minutes.