1Spray 5- to 6-quart slow cooker with cooking spray. In Dutch oven, cook beef and 3 cups of the onions over medium-high heat, stirring frequently, until beef is thoroughly cooked; drain. Stir in salt, cinnamon, cocoa, cumin and water. Simmer 2 minutes. In slow cooker, mix beef mixture, tomato puree and brown sugar until blended.
2Cover; cook on Low heat setting 8 hours.
3About 15 minutes before serving, cook and drain spaghetti as directed on package. To serve, spoon chili over spaghetti; top each serving with 1/4 cup cheese, 2 tablespoons of the remaining onions, 2 tablespoons beans and the oyster crackers.