In large saucepan combine wine, bay leaf, thyme, salt and pepper. Bring to a boil. Add scallops and reduce heat. Simmer 4 to 5 minutes until scallops are slightly firm. Drain and reserve 1 cup of the poaching liquid.

Melt the remaining 3 tablespoons of butter and add the flour, combining well. Slowly whisk the reserved scallop broth and cream. Cook until thickened. Remove from heat and fold in the cooked mushrooms and scallops.

Spoon into 6 large scallop shells (or casserole dish) and sprinkle with buttered crumbs. Top with Gruyere. Bake at 400 degrees for 10 minutes.