An ice making assembly (200) and a refrigerator appliance (100) comprising the ice making assembly (200). The refrigerator appliance (100) comprises a cabinet defining a chilled chamber, a door (128), an icebox (150) mounted to the door and defining an ice making chamber (154), and an ice making assembly (200) positioned within the ice making chamber (154). The ice making assembly (200) comprises: an resilient mold (210) defining a mold cavity (212); a fill cup (214) positioned above the resilient mold (210) for selectively filling the mold cavity with water; a heat exchanger (220) in thermal communication with the resilient mold to freeze the water and form one or more ice cubes; and a heating element (312) in thermal communication with the fill cup for selectively heating the fill cup to prevent ice jams or clogging.