Peel and chop the garlic and onions. Fry half of them in 1 tbsp. hot oil. Add spinach and steam for about 10 minutes. Season with salt and pepper. Cool and drain well.
Peel, wash and finely dice the carrots. Fry in 1-2 tbsp. oil with the remaining onions and garlic. Fry the tomato paste briefly. Stir in tomatoes and juice, bring to the boil. Season with salt, pepper, basil and some sugar.
Simmer for about 10 minutes. Add cream, season to taste. Cut mozzarella into slices.
Mix spinach and ricotta, season and fill into a piping bag without spout. Pour into the cannelloni. Place in an ovenproof dish and pour the sauce over. Spread the parmesan and mozzarella on top.
Bake in a hot oven (electric oven: 175°C/circulating air: 150°C/gas: level 2) for approx. 45 minutes. Garnish with olives and basil.