Confectioners' sugar plus apple sauce, jam, stewed fruit, or fresh fruit, for serving
Instructions
Make The Custard: Heat the oven to 400ºF and arrange a rack in the middle. Combine the raisins and rum in a small bowl and set aside. Whisk the egg yolks, milk, flour, salt, vanilla and lemon zest together in a large bowl. Whisk until smooth then set aside to stand for 10 minutes.
Whip The Egg Whites: In a second bowl, using an electric mixer, beat the egg whites on medium-low speed until frothy, about 2 minutes. Add the sugar, increase the mixer to medium and beat until glossy, soft peaks form, about 3 to 4 minutes more. Stir one-third of the egg whites into the yolk mixture until fully combined. Then gently fold the remaining egg whites into the yolk mixture until fully incorporated.
Bake The Pancake: In a 12-inch ovenproof frying pan, melt the butter over medium heat until foam subsides. Swirl the pan to distribute the butter, then pour in the batter and sprinkle the raisins and any remaining rum over the surface. Transfer the pan to the oven and bake until top is puffed, and both sides are golden brown, 15 to 18 minutes.
Cut Up The Pancake And Serve: Remove the pan from the oven and divide the pancake into rough 1 to 2-inch pieces using spatula or two forks. Return the pan to the stove and cook the Kaiserschmarren over medium heat, tossing frequently until the torn edges are caramelized, about 5 minutes more. Remove the pan from the heat and dust generously with confectioners’ sugar. Serve with applesauce, jam or fruit, as desired.