Preheated oven to 200C | 390F.
Cook the onion in a pan sprayed with cooking oil until translucent. Add the ground turkey and garlic powder, breaking up the turkey with your wooden spoon and cook until browned. Drain any excess liquid from the turkey and set aside.
In a large mixing bowl, stir together the spinach, ricotta, egg, egg whites, mozzarella, cooled turkey and onion mix, vegetable stock powder, parsley, basil and oregano. Mix well!
In the same frying pan, fry onion, garlic and capsicum/bell peppers, to make sauce. Add the soup and stock powder and simmer on low heat. Once slightly thickened, add stock powder and cream. Reduce heat until cream has cooked through.
In a large baking tray, spread 1/2 of the tomato sauce. Stuff each cannelloni tube until full. Repeat with all cannelloni.
Arrange the prepared cannelloni in a single layer on top of the sauce in the baking tray. Pour the remaining sauce evenly over the cannelloni. Sprinkle with the additional Mozzarella and Parmesan cheeses.
Cover the tray with foil and bake the cannelloni for 20 minutes. Remove foil and change oven settings to grill/broil for a further 10 minutes, or until cheese is golden.
Serve the cannelloni with extra creamy tomato sauce from the baking tray and garnish with fresh herbs.