Healthy Beef Chili

Name: Healthy Beef Chili
Ingredients: 1 tablespoon vegetable oil, such as safflower; 1 medium onion, chopped; 4 garlic cloves, chopped; Coarse salt and ground pepper; 2 tablespoons tomato paste; 2 tablespoons chili powder; 2 tablespoons unsweetened cocoa powder; 1 pound ground beef sirloin; 2 cans (14.5 ounces each) diced tomatoes in juice; 2 cans (14.5 ounces each) pinto beans, rinsed and drained; Toppings, such as reduced-fat sour cream, sliced scallions, and baked tortilla chips, for serving (optional)