2: Trim the tail, cut them lengthwise into 2 pieces, then hollow out the inside with a Parisian apple corer, ideally, or failing that, a small spoon.
3: Place the hollowed-out zucchini halves on a sheet of baking paper on a baking sheet, and sprinkle with fine salt.
4: Tip: To keep the zucchini firmly in place on the baking sheet, remove a slice from the bottom with a vegetable peeler or knife, to make a flat base.
5: Cut 2 slices bread into small, long pieces, the size to fit into the zucchini hollows.
6: In a small frying pan over medium heat, melt 30 g butter, and when hot, add the bread pieces. Brown well, then set aside. Preheat your oven to 180°C (360°F).
7: Back to the zucchinis: Place a thin layer of Mornay sauce on the bottom of each zucchini (a piping bag is ideal).
8: Place a piece of toast on top and press down a little.
9: Top with another generous layer of Mornay sauce.
10: Sprinkle a layer of breadcrumbs on top, followed by a layer of grated cheese.
11: Bake in the oven for about 20 minutes, watching for browning.
12: Enjoy warm or hot.
Remarks
If you don't have Mornay sauce, a béchamel sauce will do the trick. At the end of cooking, if the zucchinis are tender but the top is not sufficiently gratinated, don't hesitate to give the oven a little broil.