I'm pretty confident we could steal The Though Emporium's Single use thermite based instant hot dog [1] design and make instant packaged toast, fresh to order

[1] - https://www.youtube.com/watch?v=8X1_HEJk2Hw

Each morning you get an envelope with a slice of toast in your mailbox.

"The perfect slice, every time. No muss no fuss."

Seems to me if it doesn't also apply uniform melted butter it would be a hard sell.

Best thing since sliced bread.