Pour the pineapple rings into a sieve and drain. Cut the rings into very small pieces. Mix flour and baking powder in a mixing bowl. Add quark, milk, oil and a little salt and knead with the dough hooks of the hand mixer to a smooth, supple dough, possibly kneading to the end with your hands. Roll out the dough rectangularly (approx. 40 x 45 cm) on a floured work surface. First cut the dough into 6 rectangles of the same size, cut them in half diagonally.
Halve or quarter the ham (in the size of the triangles). First cover the triangles with ham, then sprinkle with pineapple. At the end spread each with approx. 1 tsp. chilli sauce. Roll up the triangles from the short side to croissants
Put the croissants on 2 baking trays lined with baking paper and bake them one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 20 minutes. Remove the croissants, let them cool down and serve lukewarm or cold