1. Preheat broiler to high.
2. Cut bell pepper in half lengthwise; discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 8 minutes or until blackened. Wrap peppers in foil; let stand 5 minutes. Peel and chop.
3. Combine corn, milk, and 1 tablespoon butter in a saucepan. Bring to a simmer; cook 10 minutes. Stir in stock; keep warm over low heat.
4. Melt remaining 1 tablespoon butter in a large saucepan over medium-high heat; swirl to coat. Add onion and garlic to pan; sauté 3 minutes. Stir in rice, salt, and black pepper; sauté 2 minutes, stirring constantly. Stir in wine; cook 30 seconds or until liquid almost evaporates, scraping pan to loosen browned bits. Reduce heat to medium. Stir in 1 1/2 cups corn mixture; cook 3 minutes or until liquid is nearly absorbed, stirring constantly. Reserve 1/2 cup corn mixture. Add remaining corn mixture, 1 cup at a time, stirring frequently until each portion of corn mixture is absorbed before adding the next (about 20 minutes total). Remove pan from heat; stir in 1/2 cup corn mixture, bell pepper, and green onions.