In a pan, combine scallops and 1 cup of the broth and bring to a boil; reduce heat, cover, and simmer gently for about 5 minutes or until scallops are just opaque throughout. Remove from heat; let scallops cool in liquid. Drain cooled liquid into a pint measuring cup. Add wine, if necessary, to make 2 cups liquid; reserve. Cover scallops and chill.
In a wide frying pan, melt 2 tablespoon butter over medium-high heat and add mushrooms and lemon juice. Cook, stirring, until mushrooms are golden brown and all liquid is evaporated. Pour into a small bowl and set aside.
To frying pan, add remaining 2 tablespoon butter and the onion. Cook over medium-high heat, stirring, until onion is soft but not browned. Stir in flour and cook until bubbly. Remove pan from heat and, using a wire whip, gradually stir in reserved scallop liquid. Return to heat and bring to a boil, stirring; cook until thickened (about 10 minutes). Add mushroom mixture, cream, and 1/2 cup of the cheese; stir until blended. Cover sauce and chill.
When sauce is cold, stir in scallops along with parsley and salt to taste. Divide scallop mixture equally among 4 to 6 individual ramekins and sprinkle remaining 1 cup cheese evenly over top, dividing equally among ramekins. Cover and chill until ready to bake (up to 24 hours).
Preheat oven to 400oF. Bake, uncovered, until bubbling and edges are beginning to brown (about 12 to 15 minutes).
From the Dinner Co-op