Summer Stuffed Onions with Fresh Mint, Dill and Parmesan Cheese

With a fresh, herby sauce enveloping the chopped onion and petits pois in the centre of a soft half-onion shell, these stuffed onions make an appetizing cold first course. You can use other tender fresh herbs in the sauce, or you can use feta cheese instead of Parmesan. Don’t chill this dish before serving because the flavour is best at room temperature.