Cook the tortellini al dente according to the instructions on the packet.
Cut the onion into small pieces and sauté in a little olive oil. Add the thawed spinach and sweat briefly. Cut the gorgonzola into small pieces and stir into the spinach. Add a little cream or milk and stir until a creamy mixture is formed. Season with salt, fresh pepper and nutmeg and stir in the tortellini.