About a half hour before we want to eat, we begin by pre-heating the oven to 400 degrees. Next we peel off the skin from the cooked potato and chop it into a small dice. We get about 1½ cups of potato. We set these aside on a plate.
We start heating our non-stick pan with a teaspoon of the oil over medium-low heat. Meanwhile, we finely chop our onion, yielding 1/3 cup. We add this to the pan and stir. Next we chop our piece of zucchini into a small dice, yielding ¾ cup. The onion is not yet translucent, so we stir the onions and remove the fish from the fridge.
We rinse and pat dry the two large fish fillets. They are thin pieces of fish so we do not bother removing the skin now, we’ll wait until they are cooked. We place them skin-side down in an 8-inch square baking dish, tucking the narrower ends under to allow the pieces to fit in the pan. Now that the fish is in the pan, we wash our hands. We sprinkle the fillets with salt and pepper, add a total of ½ tablespoon of butter on top in 2 pats, pour on the wine and sprinkle with a little Old Bay Seasoning. We cover the baking dish with aluminum foil and place in the pre-heated oven.
We add the zucchini to the cooking onions and stir. We put our frozen, defrosted vegetables in a fine strainer and place under the cold water to refresh. Then we mince our garlic clove by smashing it with the back-side of our knife, removing the peel, and then mincing. When the zucchini is tender, we add the carrots, peas, green beans and corn and stir to heat. Next we add the garlic, some salt and pepper, and a little more Old Bay seasoning and stir for a minute. We remove the cooked vegetable mixture to another plate.
In the same non-stick pan, we heat the remaining oil and butter over medium heat. When hot, we add the potatoes and try and get them all in one layer. We leave them alone to sear on the one side. When the potatoes and nicely browned on the bottom, we stir them with a heat-safe spatula. We continue to cook until they are browned all over.
When our fish has been cooking for 15 minutes we check to see if it is done. We want the fish just cooked through. When we remove the foil it is bubbling and when we check with a knife it is done. We remove it from the oven and keep it covered until the vegetable hash is ready.
When the potatoes and nicely browned, we sprinkle them with salt and pepper and then add the reserved vegetables to the pan. We stir in the paprika and the rest of the Old Bay Seasoning and cook for a few more minutes on medium-low heat.
We carefully remove the fish with a spatula to a large plate and flip over to expose the skin. We peel off and discard the skin. We flip the fish back over and and then serve the fish on top of the vegetable hash. We sprinkle the fish with lemon juice and serve.