How to Make It
Assemble macarons evenly on a wire drying rack. Stir together water and cocoa in a small bowl until fully combined. Using a small paint brush, dip brush into cocoa mixture; brush your fingers against the bristles, splashing each macaron with dots of chocolate to resemble speckled eggs. Flip macarons over, and repeat process on the other side. Set aside to dry.
Place 1 cake layer on a cake stand or serving plate. Top with 1 cup of the dark chocolate frosting and spread evenly. Top with remaining cake layer.
Using a small knife, carve out a 1/2-inch deep hole in the top center of cake, leaving a 1-inch border. Use a spoon to remove carved out cake from hole. Lightly frost sides and top of cake with 1 cup of the dark chocolate frosting, coating the top hole with a thin layer to hold in the crumbs.
Fill 1 large piping bag with remaining 1 cup dark chocolate frosting, and snip a small corner of the piping bag; pipe random lines and swirls on top and sides of cake to resemble a nest. Once cake is fully covered in the nest pattern, fill another piping bag with the milk chocolate frosting, and snip a small corner of bag; continue in the same pattern as the dark chocolate icing. Arrange the speckled “eggs” in the “nest” on top of the cake.