"Yes, food gives you energy." Dolce just closes her eyes... and gives up for a little bit. How can someone see GHOSTS and not see the most obvious thing that everyone knew? It's best not to question it. Because once she does it goes right back to 'Klaus is secretly a ghost.' Because ghosts didn't get energy boosts from food, after all. But she figures the ice cream might work against heat and provide resistance after all.

And then it occurs to her... "Wait. Do you not understand the resistances applied by your clothes either?" Just like a ghost. Pure aesthetics to him!