Most of the students who attend my cooking classes express a fear of cooking fish because they can't tell when it's done. This is a great dish for beginners, as baking the fish in the sauce keeps it moist while it cooks, and it's easy to check for doneness. Select U.S. farm-raised catfish for the best quality.
Preheat the oven to 350°F. Coat a 13 by 9-inch baking pan with cooking spray. Place the fish in the baking dish. Pour the olive oil over the fish and rub it inside and out to coat. Sprinkle the poultry seasoning, salt, and pepper inside and outside of the fish.
Stuff each fish with an equal amount of the green onion tops, yellow onion slices, and rosemary sprigs, plus a quarter of the smashed garlic and 1 lemon slice. Sprinkle the paprika on the fish. Place one of the remaining slices of lemon on top of each fish. Pour the green onion and butter sauce around the fish.
Place the fish, uncovered, in the oven and bake for 20 to 25 minutes, or until the fish flakes easily with a fork.
Green onion and butter sauce
In a medium saucepan, heat the olive oil over medium-high heat. Add the flour, poultry seasoning,, black pepper, and cayenne pepper, stirring for a minute to combine the spices and cook the flour. Add the onions and stir for another minute. Increase the heat to high. Add the vegetable broth or water and lemon juice. Stir constantly until the sauce thickens and bubbles. Stir in the butter.