Cook the spinach with
Bring a large saucepan of lightly salted water to the boil. Boil the gnocchi for a few minutes, until they rise to the surface of the water.
Butter a gratin dish or 4 single ones, make one layer of the gnocchi and cover with tomato sauce. Sprinkle with the rest of the grated Parmesan cheese and pass under the grill until the cheese is coloured.
These gnocchi can also be served with melted butter infused with sage leaves.