In a small skillet, combine the scallops, wine, butter and onion. Bring to a boil. Reduce heat; cover and simmer for 1-2 minutes or until scallops are firm and opaque. Using a slotted spoon, remove scallops and keep warm.
Bring liquid in pan to a boil; cook until liquid is reduced to about 2 tablespoons, about 3 minutes. Stir in flour until smooth; gradually add cream. Bring to a boil; cook and stir for 1 minute or until thickened. Remove from the heat. Stir in cheese until melted. Return scallops to skillet. Pour into a greased 6-oz. ramekin or custard cup.
In a small bowl, combine bread crumbs and butter; sprinkle over top. Sprinkle with paprika. Bake, uncovered, at 400° for 4-5 minutes or until golden brown.