Here is the recipe I use. Hope it is what you are looking for.

Wacky Cake

1 1/2 cups flour
1 cup sugar
1 tsp. baking soda
1/4 cup cocoa
1 tsp. vanilla
1 tsp vinegar
6 Tbsp. butter, melted
1 cup water

Preheat oven to 350 degrees.

In ungreased 8x8 pan, sift flour, sugar, baking soda, and cocoa. Make 3 wells in flour mixture. Put vanilla in first well, vinegar in second well and melted butter in third well. Pour water over all and mix well with fork.

Bake 30 minutes.