2 cups flour
2 cups sugar
3/4 teaspoon salt
1 cup butter
1/4 cup cocoa
1 cup water
1/2 cup buttermilk or 1/2 cup regular milk mixed with 1 tsp vinegar
2  eggs
1 teaspoon baking soda
1 teaspoon vanilla extract

1/2 cup butter
1/4 cup cocoa
1/4 teaspoon salt
6 tablespoons milk
1 pound powdered sugar (1 box or 4 cups)
2 teaspoons vanilla extract

Grease and flour a pan approximately 16 x 10 x 2 inches. Some recipes call for a 1-inch-deep jelly-roll pan or cookie sheet, but a deeper roasting pan is safer and easier to transport. A smaller, deeper pan such as one 13 x 9 x 2 inches will also work, but the baking time will approximately double.

Preheat the oven to 350 degrees.

Whisk the flour, sugar, and salt together in a large mixing bowl. Put the butter, cocoa, and water in a medium-sized saucepan and bring them to a boil. Pour the hot mixture over the dry ingredients and beat the batter smooth with a mixer or whisk. (Set the saucepan aside to make the icing.) Then add the buttermilk or sour milk, eggs, baking soda, and vanilla, and mix well.

Pour the batter into the prepared pan and bake for 20 to 30 minutes, or until lightly springy in the center; a cake tester inserted in the center should come out clean. Set the cake in its pan on a rack and cool it briefly before adding the icing, which should be started about 5 minutes before the cake comes out of the oven.

Icing

Using the same saucepan as before, bring the butter, cocoa, salt, and milk to a boil, stir them well, and remove the pan from the heat. Add the powdered sugar and vanilla and beat until the sugar is dissolved. Pour this thin icing over the warm cake and allow it to cool and set before serving. Texas Cake keeps very well for several days.