1Spray inside of 1- to 2 1/2-quart slow cooker with cooking spray. Mix all ingredients except crackers; spoon into slow cooker.
2Cover and cook on Low heat setting 1 hour or until cheese is melted. Stir until cheese is smooth; cover and cook 1 hour longer.
3Scrape down side of cooker with rubber spatula to help prevent edge of spread from scorching. Serve spread with rye bread. Spread will hold up to 2 hours on Low.