Mix the flour, baking powder, salt and hazelnuts or almonds together. Peel the apple and grate it finely, pour freshly squeezed orange juice over it so that the apple does not turn so brown. Cut the dried plums very finely and divide them well. Mix everything together with the egg, preferably with a wooden spoon, not with the food processor.
When the dough is tough, use two spoons to place heaps on parchment paper and form flat cookies (3 cm in diameter). Preheat the oven to 180 ° C, bake the biscuits for about 20 minutes, they should be golden brown and not too soft.