Texas Sheet Cake with Frosting

1 cup butter
1 cup water
1/4 cup cocoa
2 cups sugar
2 cups flour
1 tsp vanilla
1/8 tsp salt
2 eggs
1 tsp baking soda
1/2 cup sour cream

Combine butter, water, and cocoa in saucepan over medium heat; heat until butter melts. Add sugar, flour, salt, eggs, soda, sour cream, and vanilla; mix well. Pour into a 15x10x1 inch jelly roll pan. Bake at 350° for 20 minutes. Spread frosting over hot cake and sprinkle with chopped pecans.

For Frosting:
1/2 cup butter
1/4 cup cocoa
1/4 cup plus 2 Tbsp milk
1 box (1 pound) confectioners sugar, sifted
1/2 tsp vanilla

Combine butter, cocoa, and milk in saucepan; bring to boil. Add remaining ingredients and mix well with electric mixer. Spread over hot sheet cake.