Pre-heat the oven to 190 deg. C., 375 deg. F., Gas Mark 5.
Heat the olive oil in a saucepan, then add the onion and fry gently for 10 minutes until soft. Add the garlic and continue to cook for a further 2 minutes. Add the chopped tomatoes and simmer for 15 minutes. Then remove from the heat, stir in the fresh basil and season to taste.
Meanwhile, combine the filling ingredients in a bowl. Season with salt and pepper and spoon or pipe the mixture into the cannelloni tubes.
Lightly butter a baking dish and transfer the cannelloni tubes into it.
Spoon the tomato sauce over the cannelloni, and then the bchamel sauce. Sprinkle Parmesan on top and bake in the oven for 30 to 40 minutes until golden and crispy.