For the croissants, knead together flour, cold fat in pieces, curd and a little salt. Wrap in plastic wrap and refrigerate for one hour.
Finely chop ham, mix with crumbled cheese. Preheat electric oven to 175 °C Celsius.
Roll out dough on lightly floured work surface to a 40 x 400 mm square (for 4 servings). Split into 4 squares and this into 8 triangles.
Put a little of the filling in the center of each of the 8 pieces. Roll up from the wide side, bend round, place on a baking sheet lined with parchment paper.
Brush the croissants with beaten egg and sprinkle with sesame seeds. Bake for about 15 minutes (gas: level 2).