Heat oil in a large nonstick skillet over medium-high heat. Add the eggplant and next 8 ingredients (eggplant through garlic), and sauté for 5 minutes. Stir in tomatoes, and cook for 3 minutes. Stir in orzo, spinach, basil, and salt; cook for 1 minute.
Preheat broiler. Place polenta on a baking sheet coated with cooking spray; broil for 3 minutes on each side. Serve ragout over polenta; garnish with basil, if desired.