Triple-layer Chocolate Crumb Cake with Chocolate Frosting

Description
Contributed by Catsrecipes Y-Group
 * Makes 16 servings

Cake

 * 3⅓ cups cake flour
 * 1½ tsp baking powder
 * 1½ tsp baking soda
 * 1 tsp salt
 * 1½ cups unsalted butter
 * 3⅓ cups light brown sugar
 * 4 eggs
 * 4 oz unsweetened chocolate, melted, cooled slightly
 * 1 cup buttermilk
 * 1 cup boiling water
 * 1 tbsp vanilla

Frosting

 * 2¾ cups milk chocolate chips
 * ½ cup unsalted butter
 * 1 cup sour cream
 * 1½ tsp vanilla
 * ¼ tsp salt
 * 1 pound box confectioners' sugar

Cake

 * 1) Heat oven to 375°F.
 * 2) Grease 3 round cake pans.
 * 3) Line 4 standard cupcake cups with paper liners.
 * 4) Combine first 4 ingredients in bowl.
 * 5) Beat together butter and brown sugar in bowl until combined.
 * 6) Then increase speed and beat until creamy.
 * 7) Add eggs, beat well.
 * 8) Beat in chocolate.
 * 9) Add flour mixture alternately with buttermilk to egg mixture, beat well.
 * 10) Beat in boiling water and vanilla until smooth.
 * 11) Pour 3⅔ cups batter into each cake pan.
 * 12) Divide remaining batter among cupcake cups.
 * 13) Bake 20 minutes for cupcakes and 35 minutes for cake layers or until done.
 * 14) Let cupcakes cool in pans 5 min.
 * 15) Unmold.
 * 16) Cool layers in pans 15 minutes invert.

Frosting

 * 1) Melt chocolate chips in saucepan until smooth.
 * 2) Let cool 15 minutes.
 * 3) Beat butter and chocolate in bowl until creamy.
 * 4) Blend in sour cream, vanilla, and salt.
 * 5) Beat in confectioners sugar until smooth and spreadable.
 * 6) Tear cupcakes into pieces.
 * 7) Coarsely grind in food processor.
 * 8) Place 1 cake layer onto serving platter.
 * 9) Spread top with 1 cup frosting.
 * 10) Add second layer, spread with 1 cup frosting.
 * 11) Top with third layer, spread thin layer of frosting around sides and top of cake.
 * 12) Reserve 1 cup frosting for top.
 * 13) Frost side with remaining frosting, sprinkle with crumbs.
 * 14) Repeat until entire side is covered with crumbs.
 * 15) Frost top with reserved frosting.