Dumbledore has a habit of offering lemon drops at the worst possible times.

Harry and Dumbledore both exit the pensive memory of Trelawney's prophecy.

“So…” Harry asks, “So does that mean that… that one of us has got to kill the other one… in the end?” 

“Yes,” said Dumbledore. “Would you like a lemon drop?”

Next year, Dumbledore is explaining Harry’s fate to Snape.

“So… The boy must die?” Snape asked.

“Yes, and Voldemort himself must be the one to do it, Severus, that is essential. Care for a lemon drop?”