I tried this, and the short answer is yes. You can use the zucchini raw, but the cooking time isn't enough to cook the zucchini all the way through, so it ends up being a bit crunchy. If you like it that way, great! But to make it more similar to actual lasagna, you'll want to cook it a bit. I did it in the microwave in the casserole dish to reduce the amount of pots and pans to wash, but you could also boil it in water for a few minutes until it's soft.