1/2 lb fish fillet or 1 lb whole fish per person
1 onion per person, sliced garlic if desired
2 or 3 tiny fingerling potatos per person (optional; you can just eat the stew, or you can cook a little rice or pasta on the side)
1/2 can plum tomatos per person
virgin olive oil, salt, pepper
half and slice (3/8 in) the onions
In a large deep turkey roaster (non-stick) toss the onions, and potatoes, in olive oil salt and pepper and at least partially seperate the onion slices.
Broil the onions, and potatos, at least 4 in. from the broiler, tossing them once or twice, till starting to wilt and brown and soften, about 10 min.
While the onions and potatos are cooking, oil salt and pepper the fish, slice the tomatos (3/8 in)
When the onions and potatos are ready, add the tomatos and their sauce ( and sliced garlic if you wish). Broil till bubbling and slightly reduced about 10 min.
Slide the fish in on top of the sauce, and broil for about 10 min for fillet or 20 min for whole fish. Serve immediately.

Total preparation and cooking time 30-40 min.