Prepare the spinach according to the instructions on the packet and season with salt. Peel the garlic clove and add to the spinach through the press.
Peel the onion and cut into fine cubes. Mix the ricotta and egg.
Mix the spinach with the finely diced onions and the pine nuts with the ricotta. Season with salt and pepper. Then pour the spinach and ricotta mixture into the cannelloni.
Place the filled cannelloni in a greased baking dish. Pour the cream over them. Cut the mozzarella into slices and place over the cannelloni.