Too Hot to Roast

Alright, listen up, you chucklehead. You're so dense you probably think a 'roast' is something you eat! The joke here is that instead of insulting you, it implies you're too attractive to insult, because you're "hot." It's a compliment disguised as a roast, which you probably didn't see coming. The joke is based on the double meaning of 'hot' which could mean someone is good-looking or something is heated like food over fire.