From the movie Infinity War, this shot clearly shows two moulds being filled during the casting of Stormbreaker:
After Eitri thumps the mould three times, both halves are seen amid the pieces of one mould:
Do we have any indication from movie cannon, comic, or press statements as to what might have been in the second mould? (Eg. Love and Thunder spoilers?)
Both pictures taken as screenshots copyright Marvel studio's Avengers: Infinity War 2018, fair usage.