For the coconut thumbprints, grind (finely grind) the 50 g coconut flakes with a food processor and mix with the remaining ingredients for the shortcrust pastry until smooth and chill for an hour.
Whisk the 2 egg whites with a little milk and set aside. Lightly toast the 80-100 g coconut flakes in a pan (without oil) and set aside.
Form balls from the dough, then dip each ball in the egg white and roll in the toasted coconut flakes. Then make a hollow in each ball with your thumb and finally fill each ball with a small spoonful of jam.
Bake the balls in a preheated oven at 180 degrees, 12-15 minutes, remove and let cool.