Combine stock and potatoes in a large (6-8 quart) pot. Bring to a boil and keep at a high simmer until the potatoes are almost tender (about 12-15 minutes). Remove from heat. In a skillet, saute chopped bacon until crisp. Remove to paper towels with a slotted spoon. Drain off all but 2 TBS bacon grease. Add the butter to the bacon grease and saute onions over medium heat until soft. Add the flour and gently whisk until incorporated. Continue stirring flour and onion mixture for 3-5 minutes. Slowly stir in one cup of the liquid from the potatoes. When fully combined, add the onion mixture to the potatoes and carefully stir until incorporated. Add the cream and heat, stirring frequently, for 10 minutes. Season to taste with pepper and serve sprinkled with bacon. 6 servings.