-
Butter and flour two 9-inch round cake pans and preheat oven to 350 degrees.
-
In mixing bowl at medium speed, beat butter and brown sugar until blended.
-
Beat in eggs.
-
Add melted chocolate and vanilla; beat until combined.
-
In another bowl, stir together flour, cocoa, baking powder, baking soda, and salt.
-
In another small bowl, mix milk and sour cream.
-
Add flour mixture and milk mixture alternately to butter mixture, about a third of each at a time, beating after each addition.
-
(Batter will be very thick).
-
Spread batter evenly into cake pans.
-
Bake in 350 degree oven until a wooden skewer or toothpick inserted in the center comes out clean (25 to 30 minutes).
-
Cool on racks in pans for 10 minutes, then invert cakes onto racks and remove pans.
-
Cool completely before frosting.