Peel, wash and chop the potatoes. Peel, wash and slice carrots. Clean, wash and cut leek into rings. Clean, wash and slice the savoy cabbage.
Remove the stalk. Cook the potatoes in boiling salted water for about 10 minutes. Add vegetables after 5 minutes of cooking time. Drain. Put everything into a greased gratin dish. Mix sour cream with mustard and season with salt and pepper.
Pour over the vegetables. Grate the cheese and spread on the casserole. Sprinkle with almonds and bake in a preheated oven (electric: 200 °C/ gas: level 3) for 25-30 minutes. Garnish with parsley as desired and serve.