Wash the potatoes and cook for about 20 minutes. Quench, peel and let cool. Defrost peas
Separate two eggs. Mix egg yolk, quark, half cheese, 1 egg and 100 ml milk. Season with salt and pepper. Beat egg white and 1 pinch of salt until stiff and fold in. Cut the potatoes into slices
Alternately layer potatoes, peas, ham slices and quark mixture in a greased casserole dish. Sprinkle with the remaining cheese. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for 40-45 minutes
For the sauce, heat the fat in a saucepan. Briefly sauté the flour in it. Stir in 1/4 l water, 1/4 l milk and stock. Bring to the boil and simmer for about 10 minutes. Wash the chives and cut into fine rolls. Stir into the sauce. Season to taste with salt and pepper. Serve with the casserole
Drink: mineral water