For the bottom layer
1/2 cup (1 stick) butter
1/4 cup dark brown sugar
5 tablespoons cocoa (I used Hershey's Special Dark)
1 large egg, beaten
1 cup shredded sweetened coconut
1 1/2 cups finely crumbled chocolate wafer cookies
1/2 cup finely chopped nuts (such as almonds or pecans)
For the middle layer
1/2 cup (1 stick) butter
2 tablespoons heavy cream
2 tablespoons Custard Powder (such as Bird's), or substitute pudding powder (instant)
2 cups confectioners' sugar, sifted
1 1/2 tablespoons cocoa (I used Hershey's Special Dark)
For the top layer
4 ounces high-quality dark chocolate, coarsely chopped
1 1/2 tablespoons butter