Given the task definition and input, reply with output. In this task, you have to identify the named entities (NER) which are the ingredients required given its directions. Named entities are the names of the items without their quantity.

Layer crushed Ritz crackers in a casserole., Drain one can of asparagus and place over crumbs., Pour 1 can of cream of mushroom soup over asparagus., Top with crackers., Dot with butter., Bake 30 minutes in a 375 oven.
asparagus, cream of mushroom soup, cracker crumbs, butter