Cut the mozzarella and gorgonzola into small cubes, mix the cheese cubes with the mascarpone well.
Clean and wash fresh broccoli and cut into pieces. Blanch in salted water. Thaw frozen broccoli according to package instructions. Drain the broccoli well, chop it into small pieces and add to the cheese mixture. Season to taste with pepper.
Fill the cannelloni with the cheese and broccoli mixture.
Cover the bottom of a greased, flat baking dish with a quarter of the tomato sauce. Place the cannelloni close together and spread the remaining sauce over the cannelloni. Grate the parmesan cheese and sprinkle on top.
Cook in a preheated oven at 200 ° C top / bottom heat for about 30 minutes.