Wash, peel and slice the potatoes and cook in salted water for 10 minutes. Wash the broccoli, peel, cut into florets and cook in boiling salted water for 8 minutes until al dente, rinse briefly in cold water and drain in a sieve. so that it does not continue to cook. In the meantime, cut the onion and ham into small pieces and sweat them in a saucepan or pan in a little oil, add 1 lightly heaped tablespoon of flour, stir and pour in the cream and milk, stir again, bring to the boil and add salt, pepper and nutmeg to taste. If the sauce becomes too thick, you can add some broccoli brew, or vegetable broth or water. Preheat the oven to 180 to 200 degrees. Put the potatoes and broccoli in a casserole dish brushed with oil, pour the ham-onion-cream sauce over it and spread the grated cheese on top. Baked for about 20 minutes.