This dish was my mother’s favorite part of Grandma’s Christmas Eve dinner. I use Spanish mackerel, but Boston (Atlantic) will work fine; add a few minutes to the baking time for the thicker filets.
Heat oven to 450°. Place fish in a single layer in an oiled casserole dish. Rub garlic into fish and season with salt and pepper. In a bowl, combine bread crumbs, cheese, and parsley; sprinkle over fish. In a small bowl, whisk together oil and vinegar; spoon over fish. Bake 15 minutes; some of the crumbs will be browned and the pan will be crackling. Remove pan from oven and let rest 10 minutes before serving.