Mix 230g flour, 1/3 package baking powder, 115g butter, 60g powdered sugar, 2 egg yolks, and up to 2 tablespoons milk until a dough forms. Press into a 20cm (8-inch) baking dish.
Peel and thinly slice apples. Toss with roughly equal parts cinnamon and sugar, then spread over the dough.
Beat egg white until stiff peaks form, 2-3 minutes. Fold in roughly equal parts sugar and almonds, spread over the apples, and smooth with a wet knife.
Bake in a preheated oven at 160°C (320°F) for 25-30 minutes until the almond top is golden and slightly crispy.
Warm jam over medium heat for 1-2 minutes, strain through a sieve, stir in a splash of liqueur, and drizzle over the cooled cake.