Preheat oven to 350°F (175°C). Grease and line two 9-inch round pans.
In a bowl, sift flour, cocoa powder, baking powder, baking soda, and salt.
In another bowl, beat sugar, eggs, milk, oil, and vanilla until smooth.
Gradually mix dry ingredients into wet ingredients.
Stir in boiling water (batter will be thin).
Divide batter evenly between pans. Bake for 25–30 minutes or until a toothpick comes out clean.
Cool cakes completely.
Whip heavy cream, powdered sugar, and vanilla until stiff peaks form.
Drain cherries (reserve juice). Mix juice with kirsch (if using).
Slice each cake horizontally into two layers. Brush each layer with kirsch mixture.
Place one cake layer on a plate. Spread with whipped cream and top with cherries.
Repeat layers, finishing with cream on top and sides.
Cover the cake with chocolate shavings and decorate with cherries.
Chill for at least 3 hours before serving.
