Heat the water, broth, turmeric and oil. Add the cousous while stirring and allow to swell. Season with garlic, parsley, salt and pepper and set aside.
Clean the zucchini, cut in half lengthways and remove the seeds with a spoon so that a hollow is formed. Fill with the couscous mixture and cover with mozzarella slices.
Heat the olive oil in an ovenproof dish and let the sage sauté briefly. Add zucchini and season. Place the tomatoes on the right and left of the courgette boats. Bake the whole thing in the oven for a good 25 minutes at 160 °.