Servings: 12

For the cake: subheading: For the cake:
3 oz. (86 g) Unsweetened Chocolate 3 oz. (86 g) Unsweetened Chocolate
2 1/4 cups (255 g) Cake Flour, sifted 2 ¼ cups (255 g) Cake Flour, sifted
2 tsp. Baking Soda 2 tsp. Baking Soda
1/2 tsp. Salt ½ tsp. Salt
1/2 cup (1 stick, or 113 g) Unsalted Butter ½ cup (1 stick, or 113 g) Unsalted Butter
2 1/4 cups (511 g) Brown Sugar, firmly packed 2 ¼ cups (511 g) Brown Sugar, firmly packed
3 Large Eggs 3 Large Eggs
1 1/2 tsp. Vanilla Extract 1 ½ tsp. Vanilla Extract
1 cup (227 g) Sour Cream 1 cup (227 g) Sour Cream
1 cup Boiling Water or Freshly Brewed Coffee 1 cup Boiling Water or Freshly Brewed Coffee
For the fudge frosting: subheading: For the fudge frosting:
4 oz. (114 g) Unsweetened Chocolate 4 oz. (114 g) Unsweetened Chocolate
1/2 cup (1 stick or 113 g) Unsalted Butter ½ cup (1 stick or 113 g) Unsalted Butter
1 (1-pound or 453 g) package Powdered Sugar, sifted 1 (1-pound or 453 g) package Powdered Sugar, sifted
1/2 cup Milk ½ cup Milk
2 tsp. Vanilla Extract 2 tsp. Vanilla Extract

To make the cake: subheading: To make the cake:
Preheat oven to 350 degrees F. Grease and line with parchment two 9-inch, round cake pans; set aside.
Melt chocolate in a small bowl over hot, not boiling, water; cool.
Sift flour, baking soda, and salt onto wax paper; set aside.
Using an electric mixer, beat butter until soft. Add brown sugar and eggs; beat at high speed until light and fluffy, 5 minutes. Beat in vanilla and cooled, melted chocolate.
Stir in dry ingredients alternately with sour cream, beginning and ending with the dry and beating well with a wooden spoon after each addition until batter is smooth. Stir in boiling water (batter will be thin).
Divide batter between pans and bake 35 minutes, until centers spring back when lightly pressed with finger.
Cool layers in pans on wire racks 10 minutes; loosen around edges with small spatula, turn out onto wire racks, and cool completely.
To make the fudge frosting: subheading: To make the fudge frosting:
Melt chocolate and butter in small heavy saucepan over low heat; set off heat. Beat powdered sugar, milk, and vanilla in medium bowl until smooth. Add chocolate mixture. Set bowl in pan of ice and water and beat with wooden spoon until good spreading consistency, so frosting will hold its shape.
To assemble cake: subheading: To assemble cake:
Put one layer on serving plate, spread with about one-fourth of frosting. Add second layer, then swirl remaining frosting over top and sides of cake.