Beat butter with sugar and egg until airy. Sift flour, salt, baking powder into a bowl. Gradually pour flour into the butter-egg mixture, alternating with sour cream.
At the apple, remove the core, peel and cut into cubes.
Pour apple cubes into the dough, mix gently.
On a baking sheet covered with parchment paper, spread the dough with a teaspoon, place the dough heaps at a distance from each other.
Bake apple cookies for 15 minutes at a temperature of 200 * C. Cool on a wire rack.