Schneewittchenkuchen (Snow White Cherry Sheet Cake)

Instructions

1. Make the pudding first. Whisk 100 ml of the whole milk with the granulated sugar and cornstarch. Bring the remaining milk to a boil with the vanilla bean and seeds, remove the pod, whisk in the cornstarch mixture and boil, whisking, until very thick, 1 to 2 minutes. Press plastic wrap onto the surface and cool to room temperature, about 1 1/2 hours (do not chill).
2. Heat the oven to 350°F (175°C). Butter the pan and line it with parchment.
3. For the cake, beat the softened unsalted butter, granulated sugar, vanilla extract and fine salt until pale and fluffy, about 4 minutes. Beat in the eggs one at a time. Whisk the all-purpose flour with the baking powder and mix it in alternately with 100 ml of the whole milk until smooth.
4. Spread a little more than half the batter in the pan. Stir the cocoa powder and the remaining 30 ml whole milk into the rest of the batter and spread it over the light layer. Scatter the drained sour cherries over the top and press them in lightly; they sink as the cake bakes and make the marbling.
5. Bake until risen and a skewer in the center comes out clean (apart from cherry juice), 35 to 40 minutes. Cool completely in the pan on a rack, about 1 hour.
6. For the buttercream, beat the soft unsalted butter until very pale and creamy, about 5 minutes. Beat in the room-temperature pudding one spoonful at a time until smooth and fluffy.
7. Spread the pudding buttercream evenly over the cooled cake and chill until firm, about 1 hour.
8. For the glaze, melt the dark chocolate and unsalted butter over barely simmering water, stirring until smooth, about 3 minutes. Cool 5 minutes, pour over the chilled buttercream and spread quickly into a thin, even layer. Chill until set, about 30 minutes, then cut into 20 pieces with a hot knife.