Heat the oven to 350 degrees F.
Pat the fish dry and season it well with kosher salt and black pepper on both sides. Arrange the fish in a large pan and add the zucchini and onions next to it and season them with salt and pepper.
In a small mixing bowl, add the garlic, spices, lemon juice, and olive oil. Whisk to combine.
Pour the sauce all over the fish and vegetables.
Bake in the heated oven for 7 to 10 minutes, then carefully remove the pan and sprinkle the grated parmesan all over the fish and vegetables. Return the pan to the oven and bake for another 3 to 5 minutes or so until the fish is flaky and the cheese has melted some.
