Warm 1/8 litre of milk lukewarm. Mix flour, yeast, 1 pinch of salt, milk and 4 tablespoons of oil to a smooth dough. Cover and leave to rise in a warm place for 30 minutes. In the meantime, peel and halve the onions and cut them into fine rings.
Clean, wash and cut the leek into rings. Heat the remaining oil in a pan. Sauté the vegetables in it. Season with salt and pepper and let it cool down. Mix the remaining milk and eggs. Season with salt, pepper and nutmeg.
Knead the dough again. Halve the dough and roll out a circle (approx. 20 cm Ø). Grease 2 forms of (approx. 18 cm Ø). Put the dough into the moulds and press the rim firmly. Prick the base several times with a fork.
Spread the vegetables over it. Pour egg milk over it. Cut bacon into small pieces and put them on the vegetables. Bake the onion cake in a preheated oven (electric range: 200 ° C/ convection oven: 175 °C/ gas: level 3) for 30-35 minutes.
Remove the onion cake and garnish with parsley.