Peel potatoes, cut into bite size cubes and place in sauce pan of water. Do not cook as yet. In a deep skillet, fry bacon crisp, set aside. When cooled, crumble bacon into very small pieces. Pour off all bacon grease except 2 tablespoons. Bring potatoes to a boil to cook. Chop enough onion for 2 tablespoons and put in skillet, add butter to bacon grease and cook onion on medium high heat until soft. Add crumbled bacon and stir to mix. Add flour to make a brine and slowly add milk to make a gravy. Stir often. As gravy begins to thicken, add more milk. Salt and pepper gravy to taste while it cooks. Reduce heat a little, to about medium. When potatoes are tender, drain excess water, and stir potatoes into gravy. Reduce heat to simmer for 10 minutes.