Pearl Drake's Potato Soup

4 cups potatoes, cubed and peeled
1 cup sliced celery
1 cup chopped onion
2 cups water
2 tbsp salt
1 cup milk
1 cup heavy cream
3 tbsp butter
1tbsp parsley flakes
1/8 tsp pepper

Cook potatoes, onion, and celery in water for 20 min, then drain, mash, and mix in remaining ingredients. Simmer for at least 30 min on low heat, or until desired consistency is acheived.