Bring a large pot of water to boil for the elbow macaroni. Add 1 tablespoon salt to water. Cook macaroni according to package directions until al dente, about 6 minutes. Drain and rinse. Spray inside slow cooker with non-stick cooking spray. Add all ingredients, saving about 1/4 cup cheddar, and stir. Cover and cook on high for 2 to 3 hours, stirring twice. Sprinkle with reserved cheddar and cover until melted. ENJOY!