Clean the spinach, wash it thoroughly and steam it briefly in a large pot until it collapses. Peel garlic and press it through a garlic press or chop it finely. Dice the ham.
Heat 2 tablespoons of oil in a frying pan. Sauté the garlic in it. Add ham and spinach and cook for 2 minutes. Season with salt and pepper. Leave to cool. In the meantime peel and chop the onions.
Chop the tomatoes while still in the can. Heat the remaining oil. Brown the onions in it. Add the tomatoes. Season with herbs from Provence, cook for about 5 minutes. Season to taste with salt and pepper. Stir in 1 tablespoon of parmesan cheese.
Fill the spinach and ham mixture into the cannelloni with a teaspoon. Place in an ovenproof dish. Pour the tomato sauce over the cannelloni. Sprinkle with the rest of the Parmesan cheese. Cover the mould with aluminium foil. Bake in the preheated oven (electric cooker: 225 ° C/ gas: level 4) for about 30 minutes.
Remove foil and bake for another 10 minutes until golden brown. Sprinkle with parsley leaves before serving.