Defrost puff pastry sheets. Cut ham and onions into cubes. Steam ham, garlic and onions in butter until soft, season with pepper, nutmeg and salt and cool. Add cheese, crème fraîche and parsley and spread on the puff pastry form, leaving an edge free. Brush the edges with egg white. Fold into triangles, smoothing the edges well. Place the pockets on parchment paper/sheet and brush with the egg yolks mixed with whipped cream. Bake at 180 °C convection oven for about 20 minutes.
Tip: Always use an aromatic ham, it gives your dish a wonderful touch!