The Best Chocolate Cake (Really!)

Preheat oven to 350°F.
Melt chocolate, either on the stove or in the microwave and set aside.
Beat butter in large mixer bowl then add brown sugar and eggs, and beat until light and fluffy, about 5 minutes.
Add vanilla and melted chocolate, and beat to combine.
Combine flour, baking soda, and salt and add to chocolate mixture gradually, alternating with sour cream, beating after each addition.
Stir boiling water into the batter - the batter will be thin.
Pour into two 9 inch round cake pans which have been greased and floured.
Bake for 35 minutes, until cake centre springs back when touched.
Cool for 10 minutes before removing from pans. Allow to cool completely before applying frosting.
***For the frosting***.
Combine brown sugar, butter and milk in a small saucepan and bring to a boil.
Continue to boil, stirring constantly, for 3 minutes.
Cool to lukewarm.
Stir in icing sugar and continue to stir until the right consistency to spread.
(There should probably be a small film wanting to form on top ideally, but no real crystalization.) Spread over cooled cake.