In a pressure cooker, cook bacon over medium heat until crisp. Remove with a slotted spoon to paper towels. In the drippings, saute leeks and onion until tender. Add potatoes and broth. Close cover securely; place pressure regulator on vent pipe.
Bring cooker to full pressure over high heat. Reduce heat to medium-high and cook for 5 minutes. (Pressure regulator should maintain a slow steady rocking motion; adjust heat if needed.)
Remove from the heat. Immediately cool according to manufacturer's directions until pressure is completely reduced. Uncover; cool soup slightly. In a blender, process soup in batches until smooth. return all to the pan. Add cream and parsley; heat through over medium-low heat (do not boil). Season with salt and pepper. Garnish with bacon.