1/2 pound salmon filets
2/3 cup dry white wine
1 Tbsp. parsley
4 ounces sliced white button mushrooms
4 Tbsp. butter, divided
2 Tbsp. flour
1/3 cup half and half
1/2 pound peeled and deveined raw large shrimp
3/4 cup frozen peas and carrots
1 1/2 pounds potatoes, either Russet or Yukon gold, peeled and cut into chunks
Cook the potatoes in boiling water for 15 to 20 minutes, until tender. Drain and mash the potatoes with a potato masher. Add a tablespoon of the butter, a splash of half and half, and continue to mash until smooth. Season with salt and pepper to taste.
While the potatoes cook, generously season the cod and salmon filets with salt and pepper and place them in an even layer in the bottom of a 1 1/2 quart casserole dish. Pour the wine over the fish and sprinkle with parsley. Cover the dish with foil and bake at 350 for 15 minutes.
Meanwhile, in a skillet, heat 1 tablespoon of butter over medium heat. Add the mushrooms, and cook for about 5 minutes, stirring pretty regularly. Remove to a bowl or plate. In the same skillet, melt 2 tablespoons of the butter. As it just begins to brown, add the flour. Cook, stirring, about 2 minutes. Reduce heat to low.
Remove the baking pan with the fish from the oven, and use a slotted spoon to move the fish filets to a cutting board. Pour the liquid from the baking dish into the skillet, and whisk until the smooth. Bring the heat up to medium, and whisk constantly until the mixture boils. Add the half and half and season with salt and pepper. Remove from the heat. Stir in the frozen vegetables.
Cut the fish into chunks, and place them back into the casserole dish. Top with the cooked mushrooms, and then the shrimp.
Pour the sauce over the mixture in the pan and then smooth the mashed potatoes over the top. Sprinkle with additional parsley if you like. You can also rake a fork through the potatoes if you want to make a fancy design!