Preheat oven to 375. Melt butter in saucepan. Blend in flour, salt, pepper, and nutmeg; cook 1-2 minutes. Gradually add milk; cook, stirring, until slightly thickened. Stir in frozen vegetables. Remove from heat; stir in cheese until melted. Add lemon juice, turkey, mushrooms and broccoli. Pour mixture into a lightly greased 8"x8" baking dish; sprinkle with Parmesan and top with biscuits. Bake 20 minutes, or until biscuits are golden brown.
