3medium zucchinitrimmed, sliced lengthwise into ¾-inch slices
4medium purple or yellow onionsrinsed, sliced in half, skin left on
1bigfat eggplant or 2 medium eggplant, cut in ¾-inch slices
4medium mackerel or other fishcleaned
4 to 6thick slices of bread
Many fresh or dried bay leaves
Place the oil and the salt on a flat platter, mix.
Paint the zucchini, the cut side of the onions and the eggplant slices with the oil and salt mixture.
Skewer the cherry tomatoes, then paint them with oil and salt.
Rub the mackerel with the oil mixture, and rub oil onto the bay leaves.
Light all the burners on the gas grill. When it has reached 450F, place all the ingredients on the grill. Cover the grill and let the ingredients cook for 8 minutes.
Return to the grill and turn everything. Close the grill. After 5 minutes check the ingredients. The fish will be cooked, so carefully transfer it to a platter. It will leave its skin on the grill. Transfer the zucchini and the tomatoes to the platter that held the oil and the salt.
If the bay leaves are nice and dark, remove them from the grill.
Turn the eggplant slices, cover the grill.
Paint the bread with olive oil.
After 4 minutes, place the bread on the grill directly over the flames. Check and remove any eggplant slices that are grilled to your liking. Close the grill for about 2 minutes and remove the bread, which will be perfectly toasted on one side, and crisp on the other, and the remaining eggplant slices.
Roll the vegetables around in any remaining oil and salt. Serve all.