Cut bacon into inch strips and fry until crisp. Reserve crisp bacon for garnish and use 3 Tbsp. of rendered bacon fat or butter to saut onion over medium heat until tender but not browned. Add chicken stock and potatoes and simmer for 20 to 30 minutes or until potatoes are tender. Remove potatoes with stock from heat and add half and half. Simmer 15 minutes, then remove from the heat and cool to room temperature. Place mixture in blender. Blend until smooth then strain mixture soup if desired, otherwise, return soup to a soup pot and reheat. Finish soup with cup sour cream then season soup with salt & pepper to taste.