It would help if Bellatrix could cook, herself, but she'd never had the time, inclination or desire to learn. Nor really the opportunity - Everything got handed to her on a silver platter. A tarnished, smudged and polished silver platter, but still, a silver platter.
She took a different route than usual home, to preserve the surprise the longest, "Busy. I've been editing and re-editing the new dvds and they're still not perfect."