Make the béchamel sauce and set aside. Cook the spinach in boiling salted water for about 5 minutes. Drain well and chop finely.
Heat the olive oil in a saucepan. Add the garlic and as soon as it begins to sizzle, add the spinach. Lower the heat and cook for 5 or 10 minutes.
Add the béchamel, the pine nuts and the Parmesan cheese and heat through. Add a grinding of black pepper.