Boil potatoes, let cool, peel and slice. Slice the sausages, dice the onion.
Peel and slice the carrots, cut the leek into rings.
Fry the sausage slices and onion in a little oil. Add the carrots and leek and fry briefly. Pour in the soup, cover and cook until al dente.
Mix the crème fraîche with a some Gouda.
Preheat the oven to 200°C. Grease the casserole dish. Layer the potatoes and vegetable mixture alternately. Spread the cheese cream in blobs and sprinkle with the remaining Gouda.
Place in the oven for 15-20 minutes on the middle shelf.