Thaw the spinach leaves. Then squeeze out and roughly chop. Peel and finely chop onions and garlic and fry in hot olive oil. Add the spinach and cook for about 5 minutes. Season to taste with salt, pepper and nutmeg. Let cool and mix with ricotta, 40 g parmesan and the egg. Pour the mixture into a piping bag with a large perforated nozzle and inject into the cannelloni.
Place the cannelloni side by side in a greased baking dish. Mix the pasta sauce and vegetable stock, bring to the boil and pour over the filled cannelloni. Scatter 20 g of parmesan on top. Bake in a preheated oven at 200 ° C for about 35 minutes.