What appears to be a tomato sauce is in fact carrot and beet based. The diet here tends away from nightshades, so tomatoes are a rarity. I was a bit skeptical but this actually turned out to be very, very tasty.
What would normally be a ricotta type layer was tofu and cabbage with corn, and the meat sauce type layer was the carrot beet sauce with mushrooms and seitan (wheat gluten). Once again, might sound crazy, but this is deep in the running for one of the better lasagnes of my life. Rich in flavor and very satisfying.