Wash the pumpkin, quarter it, remove the seeds and fibers and cut into thin slices. Peel the potatoes and cut them into thin slices.
Grease a baking dish with butter, mix the potato and pumpkin slices, season with herbal salt, pepper and nutmeg, mix well again and layer in the baking dish. Peel and finely chop the garlic and spread over the vegetables with the cream.
Grate the Gouda cheese and mix it thoroughly with the finely chopped rocket and olive oil and also spread over the gratin. Cook at 180 ° C for about 50 - 60 minutes.