Brush each fillet with olive oil and season with salt and pepper, dredge, skin side down in the herb/bread mixture. Heat 2 tablespoons of the oil in a large saute pan until almost smoking. Add the fillets, crust-side down and saute until lightly golden brown, about 3 to 4 minutes. Reduce heat to medium, turn the fillets over and continue cooking until the fish is just cooked through, about 3 to 4 minutes more.
Preheat oven to 350 degrees F. In a medium casserole, make a layer of onions, drizzle with a few tablespoons of olive oil, season with salt and pepper and sprinkle with some of the herbs. Repeat with the remaining vegetables. Cover and bake in the oven for 1 to 1 1/2 hours, pressing down on the vegetables occasionally, until the vegetables are completely tender. Garnish with fresh parsley.