Preheat the oven to 375 degrees. Grease and flour 3 9-inch cake pans.  (I use cocoa instead of flour)

Melt chocolate in microwave for 1 minute power level 7. Stir and then do 30 seconds power level 7 until it is melted completely. Cool.*

In a large bowl beat butter until soft and creamy. (If butter is not at room temperature you can soften it in the microwave in the paper wrapper for 10 seconds.)

Add the brown sugar and eggs and beat with an electric mixer for 5 minutes at high speed. Scrape down several times during this process.

Beat in the vanilla and melted chocolate.

Stir flour, baking soda and salt with a fork to aerate and incorporate the salt and soda. Add flour mixture alternately with sour cream, beating well after each addition. Stir in boiling water slowly and mix well. Batter will be thin.

Pour evenly into prepared pans. Bake for 25 minutes or until sides of cake shrink from edge of pan and a tester inserted comes out with just a few moist crumbs.

Cool on rack.

Chocolate Fudge Frosting

Combine chocolate and butter in microwave safe bowl. Microwave on power level 7  until mixture is fully melted. Do this in 30 second intervals and whisk the chocolate and butter in between until melted and chocolate and butter are incorporated.

Combine sifted confectioners sugar, milk and vanilla in mixing bowl. Stir until smooth. Add the chocolate mixture. Beat until well combined. If frosting is too soft to be spreadable,  place bowl in a pan of ice water and beat with a spoon until frosting is thick and holds its shape. This can also be refrigerated and brought to room temperature before icing.