1. Prepare Meatballs: Preheat oven to 400°. Combine first 2 ingredients in a bowl; let stand 10 minutes. Stir in egg and next 11 ingredients until blended. Add pork; combine using your hands. (Do not overmix.) Shape into 36 (1-inch) balls. Lightly grease a jelly-roll pan with cooking spray. Place meatballs in pan. Bake 10 minutes.
2. Prepare Ragu: Process onion and next 3 ingredients in a food processor 20 seconds or until finely chopped; transfer to a bowl. Process tomatoes, in batches, until smooth.
3. Sauté onion mixture in hot oil in a Dutch oven over medium heat 17 to 20 minutes or until tender. Add wine and 1/4 tsp. salt, and cook, stirring occasionally, 3 minutes. Stir in broth, basil, tomatoes, and remaining 3/4 tsp. salt. Bring to a boil; reduce heat to low, and simmer, stirring occasionally, 35 minutes; add meatballs, and cook 10 minutes. Discard basil. Stir in lemon zest and salt and pepper to taste.
4. Prepare Polenta: Bring 8 cups water and 1 1/4 tsp. kosher salt to a boil in a 4-qt. saucepan over medium-high heat; gradually whisk in polenta. Reduce heat to medium-low; cook, stirring occasionally, 20 to 25 minutes or until creamy. Remove from heat; stir in cream, cheese, and butter. Add salt and pepper to taste. Serve immediately with ragu.