Roast Veggies: Preheat oven to 400°F. Toss veggies with olive oil, salt, pepper, and Italian seasoning. Roast for 20 minutes, adding spinach in the last 5 minutes.
Prepare Ricotta Filling: Mix ricotta, egg, garlic powder, salt, nutmeg, and mozzarella in a bowl. Set aside.
Make Béchamel Sauce: Melt butter in a saucepan. Whisk in flour, then slowly add milk. Stir in salt, pepper, garlic powder, and Parmesan. Cook until thick.
Assemble Lasagna: In a baking dish, layer noodles, ricotta filling, roasted veggies, béchamel, and mozzarella. Repeat layers, ending with cheese on top.
Bake: Cover with foil and bake at 375°F for 30 minutes. Uncover and bake for 10-15 minutes until golden and bubbly.
Rest & Serve: Let it sit for 10 minutes, then garnish with fresh basil and enjoy!