1Cook sausage and onion in 10-inch skillet over medium-high heat, stirring frequently, until sausage is no longer pink; drain. Stir in pepperoni, ketchup and pizza sauce.
2Spray 1 1/2- to 3-quart slow cooker with cooking spray. Spoon sausage mixture into cooker. Stir in cheese.
3Cover and cook on low heat setting 2 to 3 hours or until cheese is melted and mixture is hot.
4Scrape down side of cooker with rubber spatula to help prevent edge of dip from scorching. Serve with bread or crackers. Dip will hold on low heat setting up to 2 hours. Stir occasionally.