Preheat oven to 400 degrees F.
In an oven proof skillet (cast iron, dutch oven or stainless steel), saute the onion in olive oil until soft but not browned.
CRUMB TOPPING In a medium sized bowl, combine the panko crumbs with the parsley, melted butter, 2nd tablespoon of olive oil, and the juice of half the lemon.
Once the onions are soft, add a pinch of red pepper flakes, salt and pepper.
Add the juice of second half of the lemon and the white wine to the pan with onions and continue to cook for 1 minute.
Place the fish on top of the onions and season the fish with salt and pepper.
Add the crumb topping evenly over the fish and sprinkle with parsley.
Bake for about 20 minutes until fish is cooked through and the crumbs are nicely browned.
Cover with tinfoil half way through baking if the top is browning to fast.