Mix the flour, milk powder and egg yolk powder for later use.
Beat with butter and powdered sugar until creamy, add egg yolk and beat until even. Add the mixed powder.
Put the dough into the model, squeeze out a 5cm strip, roll up the filling on one end, and arrange it on the baking tray. Spread egg yolk on the surface and bake at 150 degrees for 25 minutes or until golden brown!