Cook the pasta in boiling salted water according to the instructions on the packet. Peel and finely chop the onion. Heat 1 teaspoon of oil in a saucepan and sauté the onion. Add spinach and steam for about 6 minutes, season with salt and pepper.
Cut the salmon into cubes. Heat 1 tablespoon of oil in a frying pan and fry the salmon for 3-4 minutes while turning. Drain the noodles, rinse and drain. Grease a round casserole dish.
Pile the spaghetti into the mould. Mix eggs and milk, season with salt, pepper and nutmeg. Pour over the spaghetti. Spread spinach and salmon on top. In a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) 45-5
If necessary, cover the casserole with aluminium foil for the last few minutes.