Step 1

Preheat oven to 350 degrees.

Step 2

Mix dry ingredients in a bowl.

Step 3

Add melted butter, vanilla, water and vinegar.

Step 4

Grease a 13x9 inch pan and coat with cocoa.

Step 5

Bake for 30 minutes or until a cake tester inserted into the center comes out clean.

Step 6

Allow to cool before frosting.

Step 7

In a medium bowl, mix powdered sugar and butter with a mixer on low speed.

Step 8

Stir in vanilla and 1 tablespoon of milk.

Step 9

Gradually mix in additional tablespoon of milk until the frosting is smooth and spreadable.

Step 10

If frosting is too thick, add more milk, a few drops at a time.

Step 11

If frosting is too thin, gradually add small amounts of powdered sugar until thickened.