1. In a 3-1/2 or 4 quart crockery cooker combine potatoes, water, onion, boulillon granules, and pepper. Cover; cook on low-heat setting for 9-11 hours or on high heat setting 4 to 4-1/2 hours.
2. Stir cheese and milk into soup. Cover; cook on low-heat setting for 1 hour more or on high-heat setting for 30 minutes more. Mash potatoes slightly.