"This is the recipe of my friend's grandmother who's from Germany. I usually use pitted sour cherries in syrup (you can get them at Trader Joe's® sometimes), but you can also use fresh sweet cherries of course."
Preheat oven to 350 degrees F (175 degrees C). Grease a large, rimmed baking sheet with butter.
Combine 2 cups confectioner's sugar, 1 cups plus 2 tablespoons butter, vanilla sugar, lemon zest, and salt in a large bowl; beat with an electric mixer until smooth and creamy. Add eggs one at a time and beat well after each addition until batter is very foamy, about 10 minutes total.
Combine flour and baking powder and beat in alternately with the milk. Spread batter onto the prepared baking sheet, smoothing out with a spatula. Cover with cherries.
Bake in the preheated oven until cake is set, about 45 minutes. Allow to cool for about 30 minutes. Dust with 1 tablespoon confectioners' sugar.