Chocolate-Frosted Devil's Food Cake with Pecan and Coconut Filling

For the cake layers:
4 oz. unsweetened chocolate, chopped
1/2 cup water
3 cups cake flour (not self-rising)
1 teaspoon baking soda
1 teaspoon salt
2 sticks (1 cup) unsalted butter, softened
1 cup firmly packed light brown sugar
1 cup granulated sugar
3 large eggs
1 1/2 teaspoons vanilla
1 cup buttermilk

For the filling:
1 cup heavy cream
1 cup granulated sugar
1 stick (1/2 cup) unsalted butter
3 large egg yolks, beaten lightly
1 teaspoon vanilla
1 cup pecans, chopped fine and lightly toasted
1 1/3 cups sweetened flaked coconut, toasted lightly

For the frosting:
5 tablespoons unsalted butter, softened
3 tablespoons heavy cream
1 teaspoon vanilla
2 oz. unsweetened chocolate, melted and cooled
2 cups confectioners' sugar

Make the cake layers:
Line the bottoms of 3 buttered 9 x 1 1/2 inch round cake pans with rounds of wax paper, butter the paper, and dust the pans with flour, knocking out the excess.

In a small metal bowl set over a saucepan of barely simmering water melt the chocolate with the water, stirring occasionally, remove the bowl from the heat, and let the mixture cool.

Into a bowl sift together the flour, the baking soda, and the salt. In the large bowl of an electric mixer cream together the butter and the sugars until the mixture is light and fluffy, add the eggs, 1 at a time, beating well after each addition. Beat in the vanilla and the chocolate mixture. Beat in the flour mixture and the buttermilk alternately in batches, beginning and ending with the flour mixture, and beat the batter until it is smooth.

Divide the batter among the prepared pans, smoothing the tops, rap each pan twice on a hard surface to expel any air bubbles, and bake the layers in the middle of a preheated 350oF oven for 25 to 30 minutes, or until a tester comes out clean. Let the layers cool in the pans on racks for 10 minutes, run a knife around the edge of each pan, and invert the layers onto the racks. Remove the wax paper and let the layers cool completely. The cake layers may be made 2 days in advance and kept, wrapped in plastic wrap, at
room temperature.

Make the filling:
In a heavy saucepan combine the cream, the granulated sugar, and the butter and cook the mixture over moderately low heat, stirring, until the sugar is dissolved. Whisk 1/2 cup of the cream mixture into the yolks, whisk the yolk mixture into the remaining cream mixture, and cook the mixture over moderately low heat, whisking, for 10 minutes, or until it is thickened. (Do not let the mixture boil.) Stir in the vanilla, the pecans, and the coconut and let the filling cool, stirring occasionally.

Make the frosting:
In a bowl with cleaned beaters beat together the butter, the cream, the vanilla, the chocolate, and the confectioners' sugar until the frosting is fluffy.

Assemble the cake:
On a cake stand arrange 1 cake layer, spread the layer with 3/4 cup of the filling, and top the filling with a second layer. Spread the second layer with 34 cup of the remaining filling and top the filling with the remaining layer. Spread the cake with the frosting and spread the remaining filling on top of the cake, letting it drip down the side of the cake. The cake may be assembled 1 day in advance and kept loosely covered and chilled. Let the cake return to room temperature before serving.