Peel, wash and quarter the potatoes, cover and cook in salted water for about 20 minutes.
Clean, wash and drain the salad and cut into strips. Peel and finely chop the onion. Rinse fish, dab dry and cut into 2 or 4 pieces. Season with salt and pepper and turn in flour.
Heat butter in a coated pan. Fry the diced ham until crispy. Fry the onion and thyme briefly. Take them out.
Heat the oil in the frying fat. Sauté the fish for approx. 2 minutes on the skin side first. Then turn and fry for 3-4 minutes.
Drain the potatoes. Add the milk, warm up briefly and mash everything into puree. Fold the salad strips and ham mix into the puree. Season to taste with salt and nutmeg. Serve the mashed potatoes with cod.