In a large frying pan, melt butter over medium heat. Add shallots and cook until softened but not browned, about 2 minutes. Add mushrooms and cook, stirring occasionally, until all liquid has cooked away, 10-15 minutes.
Sprinkle Flour over mushroom and cook, stirring until well blended, about 2 minutes. Increase Heat to high add cream and cook, stirring well until mixture comes to a boil, about 3 minutes. Remove from heat and stir in chive, parsley,lemon juice, salt and cayenne. Let cool. If made in advance cover and refrigerate up to 3 days. Freeze for longer storage.