Gratin is a fairly simple dish that mostly takes care of itself in the oven. It's delightful on weekdays or on Sundays when you need to clear out the fridge.
Preheat the oven to 200 degrees Celsius (392 degrees Fahrenheit).
Peel the potatoes and celery and slice them thinly. Also, slice the leeks and place all the vegetables in a greased baking dish.
Whisk the eggs together, then stir in the milk, crème fraîche, Dijon mustard, and spices.
Pour the egg mixture over the vegetables and sprinkle with Parmesan. Bake in the oven for 45 minutes.
Cabbage Salad
Finely slice the cabbage and fennel and cut the apples into slices or cubes. Mix oil, mustard, vinegar, and honey together, then toss the dressing with the cabbage, fennel, and apples. Let it sit in the fridge until ready to serve.
Serve with meatballs, schnitzel, or similar, or enjoy it as it is.