Preheat oven to 350 degrees. Coat a 2-quart casserole dish with cooking spray.
In a large pot of lightly salted boiling water, cook the macaroni according to package directions. Drain and set aside.
Meanwhile, in a large nonstick skillet over medium-high heat, cook the beef for 7 minutes, or until no longer pink, stirring occasionally.
Add the onion, carrots, and garlic, stirring well to mix. Cook for 5 minutes, or until vegetables are tender, stirring occasionally. Remove from heat.
Add the pasta, marinara sauce and 1 cup of the mozzarella cheese, stirring well to mix. Transfer mixture to prepared baking dish. Top with remaining ½ cup mozzarella and Parmesan. Bake for 20 minutes, or until heated through.