Warm up the milk. Put flour in a bowl, make a depression in the middle and crumble the yeast into it. Add 25 g sugar and lukewarm milk and mix with some flour from the rim to a thick paste. Cover and leave to rise for 15-20 minutes. Add soft fat in pieces, 50 g sugar, salt and 3 egg yolks to the pre-dough in the bowl and knead with the dough hooks of the hand mixer to a smooth yeast dough.
Cover the dough and let it rise again for about 40 minutes. Roll out the yeast dough on a floured work surface to a rectangle (40 x 25 cm). Cut into 6 cake pieces with a dough knife. Roll up the dough pieces tightly and place them on a baking tray lined with baking paper. Leave to rise in a warm place for another 30 minutes. Whisk 1 egg yolk and 2 tablespoons of water. Brush the croissants thinly. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 15 minutes. Let them cool down.
Leave to rise in a warm place for another 30 minutes. Whisk 1 egg yolk and 2 tablespoons of water. Brush the croissants thinly. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 15 minutes. Let them cool down. Cut in half horizontally and cover with cheese and ham
2 hours waiting time