3 large boiling potatoes, peeled and cut into 1-inch pieces
1 pound bay scallops
11/4 cups milk
2 tbsp. butter
1 tbsp. flour
Salt and freshly ground pepper to taste
8 ounces white mushrooms, sliced
¼ cup dry sherry
Preheat oven to 350. Cook the potatoes in boiling salted water until tender, 12 to 15 minutes. Drain and mash. Set aside.
Drain and rinse the scallops. In a small skillet, bring the milk to a simmer over medium heat, add the scallops and cook until opaque, 12 to 15 minutes. Strain the scallops and reserve the liquid.
In a small saucepan, melt 1 tablespoon of the butter over medium heat. Stir in the flour, then gradually whisk in the reserved liquid. Cook 2 to 3 minutes. Season with salt and pepper. Reduce heat to a simmer, add the mushrooms and cook until the sauce thickens, about 10 minutes. Stir in the sherry and scallops.
Spoon the mixture into an ovenproof casserole dish and completely cover with the mashed potatoes. Dot with the remaining butter and bake until the top begins to brown, 15 to 20 minutes. Serves 6.