Plum Torte with Peeled Italian Plums

Preheat the oven to 350 degrees F (175 degrees C). Grease two 9-inch springform pans.

Cream butter in a large bowl with an electric mixer. Add 1/2 cup plus 2 tablespoons sugar, vanilla sugar, and salt; beat well to combine. Add eggs one at a time, mixing well after each addition.

Sift flour and baking powder together into a bowl. Mix into the batter in batches, alternating with milk; the batter will be quite thick. Spoon batter into the prepared pans. Place plums close together, cut-side down, over the batter.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, 30 to 40 minutes. Cool on a wire rack for 5 minutes. Run a table knife around the edges to loosen. Invert carefully onto serving plates or cooling racks. Dust with confectioners' sugar and let cool completely.