Preheat oven to 350° F.

Cook pasta in water according to package directions. Drain. Set aside.

Heat oil in medium saucepan over medium-high heat.

Add onion, bell pepper, and carrot; cook, stirring frequently, for 4 to 6 minutes, or until onion is translucent.

Add garlic; cook, stirring frequently, for 1 minute.

Add 3 cups tomato sauce and basil. Season with salt and pepper if desired; cook over low heat, stirring occasionally, for 30 minutes.

Combine spinach and ricotta cheese in a medium bowl; mix well. Set aside.

Combine mozzarella cheese and Parmesan cheese in a small bowl; mix well. Set aside.

Lightly coat a 4-quart (or 13 x 9-inch) rectangular baking dish with spray; place remaining 2 Tbsp. tomato sauce in the bottom. Top with a layer of pasta, one fourth vegetable mixture, one third spinach mixture, and one fourth cheese mixture. Repeat twice. Top with pasta, vegetable mixture, and cheese mixture. Cover with aluminum foil.

Bake for 45 minutes. Remove foil. Bake for 10 to 15 minutes, or until hot and bubbly.

Let sit for 5 minutes before cutting.