Yeah, I figured you wouldn't have asked about cheese only if you wanted to substitute veggies! (And honestly, I'm not super enamored of veggie lasagna myself. I am not making lasagna to be healthy, I'm making it because it's delicious. Cheese is delicious. Eggplant is...eggplant.)

I thought on it some more, and I think I've landed on 'try 4 eggs not 5 the first time' - you don't want the cheese layer too liquidy, as even without the meat you're still liable to get some bubble-over/dripping.

Let me know how it goes with the oven-ready prep - like I said, I've always chickened out on trying it. I should probably be less cautious, but...