Boil the gnocchi in lightly salted water for 2-3 minutes and boil the cauliflower florets in the lightly salted water for about 5 minutes. Heat a little bit of olive oil in a pan over medium heat and fry the boiled gnocchi and kielbasa slices on both sides for a few minutes.
Add the gnocchi, kielbasa slices, and cauliflower florets to a casserole dish and season with salt, pepper, and nutmeg. Add the parsley and milk to the casserole dish and grate the Swiss cheese on top.
Transfer the casserole dish to a preheated oven and cook at 350°F for 25 minutes.