Country Chocolate Cake with Milk Chocolate Frosting

Let eggs and mayonnaise sit out for 30 minutes. Preheat oven to 350°. Meanwhile, grease three 8x11/2-inch round cake pans. Line bottoms with parchment or waxed paper. Grease paper and lightly flour pans; set aside. Microwave semisweet chocolate in a small bowl at 50 percent power for 1 minute; stir. Continue heating and stirring chocolate at 10- to 15-second intervals until smooth; set aside. In a medium bowl, combine flour, cocoa, baking soda, salt and baking powder; set aside.

In a large bowl, beat brown sugar and mayonnaise for 3 minutes, scraping sides as needed. Add the melted chocolate and beat until almost combined. Add eggs and 1 1/2 teaspoons vanilla; beat until just combined. Alternately add flour and the hot water, starting and ending with flour. Beat after each addition until just combined. Divide batter among pans.

Bake in a 350° oven for 20 minutes or until toothpick inserted near center comes out clean. Cool in pans on wire racks for 10 minutes. Remove cakes from pans; remove paper. Cool completely on wire racks.

For frosting: In a large saucepan, stir chopped milk chocolate and butter until melted. Remove from heat and cool for 6 minutes. Stir in sour cream and 1 teaspoon vanilla. With an electric mixer, beat in powdered sugar on low speed until smooth and spreadable, scraping sides as needed. Use immediately; frosting sets up as it cools. (For a fully frosted cake, use 2/3 cup frosting between layers.)