Cook the cauliflower until tender in water with a splash of olive oil, salt and pepper.
Cut the fennel, leek and carrots into large pieces. Cook them al dente in water with a splash of olive oil.
Drain the water from the cauliflower, add 1 cup of cream and 40 grams of gruyere and mash.
Drain the other vegetables and spoon them into a baking dish. Mix 1 cup of cream with the parmesan, season with pepper and pour the cream over the vegetables.
Spoon the cauliflower puree over the vegetables and sprinkle the remaining gruyere on top.
Bake the vegetable dish for 20 minutes in a preheated oven at 180°C.

You can adjust the quantities to your own needs. If you are a big eater, do a lot of sports or have a heavy job, prepare larger portions but stick to the combinations. No one should leave the table hungry.