Preheat oven to 80 °C, lightly salt and pepper the plaice on both sides and turn in the sesame seed.
Peel the potatoes, cut into small cubes of about 1.5 cm and cook in the stock.
Briefly roast the plaice fillets on both sides and cover them in an ovenproof dish for about 15 minutes in the oven at 80 °C.
Add the cream to the potatoes, then add the grated cheese and let it melt at reduced heat while stirring constantly. Season to taste with a touch of freshly grated nutmeg and a little pepper.
At the same time divide the broccoli into individual florets and cook in salted water until firm to the bite.