start crafting and some fraction of second *before* it ends and the item shows up in inventory, drop another item from inventory on first empty slot where you know the item will appear. If perfectly timed the crafted item will "overwrite" the one you dragged just some fraction of seconds there, and is lost forever.

Just did this before the patch of some minutes ago. I don't know if it also works the other way around (dropping a fraction of second *after* the crafting ends).