To prepare sauce, heat a large nonstick skillet coated with cooking spray over medium-high heat. Add onion, carrot, beef, and garlic; cook 6 minutes or until beef is browned, stirring to crumble. Add wine; cook 1 minute. Add 1/4 teaspoon salt, fennel, pepper, and tomatoes. Bring to a boil; cover, reduce heat, and simmer 40 minutes.
To prepare polenta, combine milk, 1/2 teaspoon salt, and broth in a medium saucepan. Gradually add polenta, stirring constantly with a whisk; bring to a boil. Reduce heat to medium; cook 3 minutes or until thick, stirring constantly. Stir in 6 tablespoons cheese.
Spoon polenta into an 8-inch square baking dish coated with cooking spray, spreading evenly. Let stand 10 minutes or until firm. Loosen edges of polenta with a knife. Invert polenta onto a cutting board; cut into 4 squares. Cut each square diagonally into 2 triangles. Place 1 triangle on each of 8 plates; top each serving with 1/2 cup sauce, 3/4 teaspoon cheese, and 1 1/2 teaspoons basil.