01 - Preheat oven to 425°F for roasting vegetables.
02 - Toss eggplant, zucchini, peppers, onion, and garlic with olive oil, smoked paprika, salt, and pepper. Spread on large baking sheet and roast for 25 minutes until tender and lightly charred. Reduce oven temperature to 375°F.
03 - Combine lentils, crushed tomatoes, tomato paste, oregano, basil, vegetable broth, balsamic vinegar, and chili flakes in saucepan. Bring to boil, reduce heat, and simmer uncovered for 20-25 minutes until lentils are tender and sauce thickens.
04 - Melt butter in saucepan over medium heat. Whisk in flour and cook 1-2 minutes. Gradually whisk in milk, stirring constantly. Add nutmeg, salt, and white pepper. Cook until thickened, then set aside.
05 - Spread 1/4 cup lentil sauce in bottom of 9x13-inch baking dish. Layer with noodles, half the roasted vegetables, half the lentil sauce, and 1/3 of the béchamel. Sprinkle with 1/3 of mozzarella. Repeat layers. Top with remaining noodles, béchamel, mozzarella, and Parmesan.
06 - Cover with foil and bake at 375°F for 30 minutes.
07 - Uncover and bake 10-15 minutes until golden and bubbling. Rest 10 minutes before slicing. Garnish with fresh basil leaves.