Cook onions, leek, shallots and garlic in butter (butter, not oil).
Add small onions and cook just until tender.
Stir in cream, boil and stir, simmer until thickened.
Season w salt and pepper and parsley.
Spoon into greased 1.5 qt casserole, sprinkle w breadcrumbs Bake at 475 15-20 mins until breadcrumbs browned and cream bubbles.