Rinse the artichokes and remove the stems and tough outer leaves. Cut the tops off with kitchen shears, then rub the cut surface with half a lemon. Place the artichokes cut side up in a large pot of hot, salted water, and simmer with a lemon slice for about 20 minutes. Remove the artichokes, drain and scrape out the hearts and fibers with a spoon.
Preheat the oven to 200°C (approximately 400°F).
For the filling, peel the shallots and garlic, chop finely and fry in olive oil. Rinse the shrimp and pat dry. Rinse the zucchini, trim the ends and finely dice. Add the shrimp and zucchini to the pan and fry briefly. Chop the basil leaves and add to the pan. Season with salt and pepper. Drain and finely chop the mozzarella, and set half aside. Add the other half of the cheese to the pan, then remove from heat. Place the artichokes in an ovenproof dish, fill with the shrimp and vegetables and sprinkle with remaining mozzarella. Bake in the preheated oven for about 15 minutes.