Become gooey over, as cheese atop a hot burger

MELTON

Think of how warm, soft cheese might transform when it meets something sizzling.

This clue plays on the word "melt," which literally describes cheese turning gooey from heat—like on a hot burger. But it’s also a pun: "melt on" sounds like "Melton," referencing Melton Mowbray, a town famous for its cheese (though the answer is just the first part of the name). The wordplay hints at both the action and the cheese’s origin in a sneaky way.