Preheat your oven to 400°F. Toss all the vegetables (except for the spinach) with olive oil and your seasonings. Roast them in the oven for 18-22 minutes, flipping halfway through. Stir in the spinach during the last minute to wilt it slightly.

For the white sauce, melt the butter in a medium saucepan over medium heat. Whisk in the flour and cook for 1-2 minutes until it turns golden.

Gradually add the milk while whisking continuously to avoid lumps. Simmer for 5-7 minutes until the sauce thickens. Stir in the salt, pepper, nutmeg, and Parmesan cheese until it becomes smooth and creamy.

In a separate bowl, mix the ricotta cheese with the egg, the remaining Parmesan cheese, dried basil, and garlic powder until you achieve a smooth and creamy filling.

Reduce the oven temperature to 375°F. Spread 1 cup of the white sauce in the bottom of your baking dish.

Layer the ingredients in the following order: lasagna noodles, ⅓ of the ricotta mixture, ⅓ of the roasted vegetables, a layer of the white sauce, and a sprinkling of mozzarella cheese.

Repeat these layers two more times, finishing with a layer of sauce and cheese on top.

Cover the baking dish with foil and bake for 30 minutes. After that, uncover and bake for an additional 15 minutes until the top is golden and bubbly.

Let it rest for 10-15 minutes before slicing to allow the layers to set.