Chocolate Sour Cream Cake

I'm going to be honest - I don't remember ever making this cake. But apparently I did last year and brought it to something and then EVERY PERSON THERE emailed me for the recipe. You were really good, apparently, forgotten cake!

CAKE:
2 cups flour
2 cups sugar
1 tsp baking soda
pinch salt
2 sticks butter, cut up (that's a cup.)
1 cup water
1/3 cup cocoa
3/4 cup sour cream
2 large eggs
1 tsp vanilla

Frosting:
8 tbl butter, cup up
1/3 cup plus 1 tbl milk
1/4 cup cocoa
abt 4 1/2 cups confectioner sugar
1 tsp vanilla

To make the cake, preheat oven to 350.
Butter and flour a 13x9 inch baking pan.
Combine the flour, sugar, soda and salt.
In a medium saucepan, bring the butter, water and cocoa to boil over high heat, stirring to dissolve the butter. Pour into the flour mixture and whisk well. Add the sour cream, then the eggs and vanilla and beat well. Spread evenly in the pan.
Bake until the cake springs back when pressed in the center, about 35 minutes. Remove from the oven and place on a wire rack.

Meanwhile, make the frosting. Bring the butter, milk, and cocoa to boil in a large saucepan over medium heat, stirring to dissolve the butter. Gradually stir in the confectioner's sugar, then the vanilla. Pour over the warm cake. Cool the cake in the pan on the rack. Cut into pieces and serve directly from the pan.