For the Butternut Squash Filling

Preheat oven to 375 degrees F. and line a large rimmed baking sheet with parchment paper (skip this step if you're using canned pureed butternut squash).

Cut, peel, and chop your butternut squash into small, 1-inch cubes. Transfer to your prepared baking sheet and toss with 1 tablespoon of olive oil. Roast in the oven for approximately 25-35 minutes, or until fork-tender. Remove from the oven and set aside to cool completely.

Place the cooked (or canned) butternut squash, ricotta cheese, garlic, milk, salt + pepper, and nutmeg in the bowl of a large food processor. Puree until completely smooth. Add more milk if needed- you want the butternut squash filling to be thick and creamy, but too liquidy or runny. Season with salt, pepper, and additional nutmeg, to taste.

For the Spinach Ricotta Mix

Remove excess water from the thawed spinach; you can do this using a mesh wire strainer, cheesecloth, or tea cloth. Transfer the spinach to a medium bowl with the ricotta cheese, mozzarella, fresh chopped basil, salt and pepper. Mix until fully combined.

Build your Lasagna

Prepare your baking dish (I usually use a large, deep casserole dish, 12.38"L x 9.25"W x 2"H, but the one shown in the images is slightly larger). Spray dish with non-stick cooking spray of choice.

First layer - Spread 1/3 of the butternut squash puree on the bottom of the dish. Sprinkle with a thin layer of mozzarella cheese and cover with a single, non-overlapping layer of no-boil lasagna noodles (approximately 5 lasagna sheets). Gently spread half the spinach ricotta mixture over the noodles and sprinkle with mozzarella cheese. Top with a layer of sliced zucchini (see notes).

Repeat layering (second layer) - Spread 1/3 of the butternut squash mixture over the sliced zucchini layer. Sprinkle with a light layer of mozzarella cheese and top with a single, non-overlapping layer of no-boil lasagna noodles (approximately 5 lasagna sheets). Spread the second half of the spinach ricotta mixture on top of the lasagna noodles. Top with mozzarella cheese and top with a layer of sliced zucchini.

Final layer - Spread the remaining 1/3 of the butternut squash filling over the zucchini and sprinkle with grated Parmesan and mozzarella cheese. Sprinkle fresh basil leaves on top of the cheese.

Cover the baking dish with a large foil "tent" and bake for approximately 20-30 minutes. Remove foil and continue to cook for an additional 15-20 minutes, or until the cheese is bubbly and golden.

Top with additional fresh basil or sage leaves, if desired.