Zucchini and Ravioli Gratin: The Secret to an Ultra-Crispy Top Revealed in the Oven

The zucchini and ravioli gratin becomes crispier if prepared the day before. Overnight refrigeration allows the zucchini to release moisture and the cream to soak into the ravioli, creating a compact base. The reduced surface humidity promotes a golden, caramelized crust thanks to a blend of Emmental, Comté, and Parmesan cheeses. The recipe uses ravioles du Dauphiné, zucchini, onion, garlic, cream, milk, and grated cheese.