Preheat oven to 350°F (175°C).

Butter three 9-inch cake pans and line the bottoms with buttered waxed paper.

Combine chopped chocolate, 1 cup water, and espresso powder in a saucepan.

Stir over low heat until chocolate melts and the mixture is smooth.

Remove from heat and cool completely, stirring occasionally.

Using an electric mixer, beat brown sugar and butter in a large bowl until light and fluffy.

Add eggs one at a time, beating well after each addition.

Add the cooled chocolate mixture and vanilla extract, then beat until blended.

Sift together flour, baking soda, baking powder, and salt in a medium bowl.

Gradually add dry ingredients to the butter mixture, alternating with sour cream in three additions, beginning and ending with the dry ingredients. Beat well after each addition.

Divide the batter equally among the prepared cake pans.

Bake for about 30 minutes, or until a tester inserted into the center comes out clean.

Cool cakes in pans on racks for 10 minutes.

Loosen cakes from pans by running a small knife around the edges.

Turn cakes out onto racks, remove waxed paper, and cool completely.

Place one cake layer on a platter.

Spread half of the caramel-coconut almond filling evenly over the top, leaving a ½-inch border.

Top with the second cake layer.

Spread with the remaining filling, leaving a ½-inch border.

Top with the remaining cake layer.

Spread frosting over the sides and top of the cake.

Press sliced almonds onto the sides of the cake.

Using a pastry spatula, swirl frosting decoratively on top of the cake.