Crazy Cake with Cooked Buttercream Frosting

This is not one of my original recipes. I made it this weekend for my Granddaughter's 19^th birthday. She never had it before and years ago it was what I always made for my children's birthday parties. It's also a great dessert for people who can't eat eggs, since there are none in this cake or frosting.

Cake:

3 cups all-purpose flour

2 cups white sugar

1 teaspoon salt

2 teaspoons baking soda

1/2 cup unsweetened cocoa powder

3/4 cup vegetable oil

2 tablespoons distilled white vinegar

2 teaspoons vanilla extract

2 cups cold water

Sift flour, sugar, salt, soda, and cocoa together into a 9 x 13 inch un-greased cake pan. Make three wells. Pour oil into one well, vinegar into second, and vanilla into third well. Pour cold water over all, and stir well with fork. OR – Using conventional mixing method: Combine all dry ingredients in a large bowl. Mix the wet ingredients in a 3-4 cup measuring device. Pour over dry ingredients and mix with a wooden spoon. Bake at 350° F (175° C) for 30 to 40 minutes, or until tooth pick inserted comes out clean. Frost a couple hours later when cake is room temperature.

Frosting:

1 cup butter, softened

1 cup white sugar

4 tablespoons all-purpose flour

1 cup milk

1 teaspoon vanilla extract

In small saucepan, cook flour and milk until it thickens stirring constantly. Cool to room temperature. With an electric mixer, beat butter and sugar until fluffy. Add the flour mixture to the butter and sugar. Beat on high speed until fluffy and smooth. Add vanilla and beat until combined. Frost cake and store, covered in the refrigerator.