Preheat your oven to 400°F (200°C). Cut the butternut squash into small cubes, toss with olive oil, salt, and pepper, and roast for 25–30 minutes.

While the squash is roasting, heat a large skillet over medium heat, add olive oil, and sauté the spinach until wilted, seasoning with salt, pepper, and nutmeg.

In a saucepan, melt butter, whisk in the flour to create a roux, gradually add milk, and stir until thickened to make the béchamel.

In a bowl, combine ricotta cheese, grated Parmesan, salt, pepper, and herbs. Mix until smooth.

In a baking dish, layer béchamel sauce, lasagna noodles, roasted butternut squash, sautéed spinach, and ricotta mixture; repeat the layers.

Cover and bake the lasagna for 25 minutes, then uncover and bake for an additional 15–20 minutes until golden brown. Let cool before slicing.