The semolina is added in a constant stream, stirring all the time, to incorporate air and prevent lumps forming. Infuse the milk first, if you like. Bring it to the boil with seasonings such as onion, cloves and bay leaves, cover and let stand 1 hour. Strain the milk before using.
Bring 1 litre milk to the boil in a large pan. Lower the heat and pour in 175 g semolina in a steady stream, stirring constantly with a wooden spoon to prevent lumps forming.
Bring the semolina mixture to the boil and cook, stirring constantly, until thick and smooth, about 5 minutes.
Whisk together 3 egg yolks. Remove the pan from the heat and beat the eggs, a little at a time, into the semolina mixture until evenly incorporated.
Spread the mixture in a lightly oiled shallow dish. Rub the surface with a knob of butter, to prevent a crust forming. Let cool, preferably overnight.
Lightly oil a plain pastry cutter and cut the mixture into rounds or use a chef’s knife to create shapes of your choice. Arrange the gnocchi shapes, overlapping them slightly, in an oiled baking dish, brush with melted butter and sprinkle with freshly grated Parmesan cheese. Bake at 230°C for 15-20 minutes until golden brown. Serve hot.