Preheat the oven to 220 ° C. Sift the flour and baking powder into a large bowl. Add butter and grate with your fingers. Stir in the sugar, apple and cinnamon. Make a well in the middle, pour the milk into the well (keep 1 teaspoon). Mix everything into a smooth dough and place on a floured board. Knead lightly, flatten or roll out approx. 2 cm thick. Cut out slices with a round cookie cutter. Place these on a greased baking sheet and brush with the rest of the milk. Sprinkle with sugar and cinnamon. Bake the slices for 10-12 minutes.