Ladybird Diner was built to be a pie destination. When self-proclaimed pie lady Meg Heriford opened it five years ago, fans lined up for slabs of her cherry and banana cream pies. Then one day Meg whipped up a hazelnut cake with brown-butter caramel buttercream and a dark chocolate drizzle. "I don't know what came over me," she says. Soon Meg and her team were experimenting with elevated versions of coconut, German chocolate and red velvet cakes, and lines formed for the cakes just as quickly as they had for the pies. The diner's signature Black Forest cake, topped with Italian black cherries, usually sells out in less than an hour.
Make the cake: Position racks in the upper and lower thirds of the oven and preheat to 350 degrees F. Coat three 10-inch round cake pans with cooking spray and line the bottoms with parchment paper; set aside. Combine the all-purpose flour, almond flour, cocoa powder, baking powder, baking soda and salt in a medium bowl. Whisk the milk and vanilla in a small bowl. Beat the butter and sugar in a large bowl with a mixer on medium speed until fluffy, 3 minutes. Add the eggs, one at a time, beating well after each addition. Reduce the speed to low; beat in the flour mixture in three batches, alternating with the milk mixture, until combined.
Stir in the hot coffee (the batter will be thin). Divide among the prepared pans. Bake, switching the pans halfway through, until a toothpick inserted in the centers comes out mostly clean, 30 to 45 minutes. Let cool 10 minutes in the pans, then turn out onto racks to cool completely.
Meanwhile, make the ganache: Melt the chocolate chips with the heavy cream in a heatproof bowl set over a pan of simmering water (do not let the bowl touch the water). Let cool slightly. Add the cherries and let cool.
Make the buttercream: Combine the egg whites, sugar, salt and cream of tartar in the heatproof bowl of a mixer set over the pan of simmering water (do not let the bowl touch the water). Heat, whisking, until a candy thermometer reaches 185 degrees F, 5 minutes. Transfer the bowl to the mixer and beat on medium-high speed until the egg whites are stiff and glossy and the bowl is cool to the touch, 10 minutes. Beat in the butter 1 tablespoon at a time. Add the cherry liqueur and continue to beat until smooth. Beat in cherry syrup, 1 teaspoon at a time, to tint the frosting pink.
Spread half of the ganache on one cake and top with a second cake. Repeat with another layer of ganache and the remaining cake. Trim the sides of the cake with a serrated knife to make them even; crumble the trimmings. Frost the cake with the buttercream and pipe some around the top. Top with cherries and the reserved cake crumbs.