Presto German Potato Salad

This recipe came with my first Presto Pressure cooker and I have made it 1,000 times, and adapted it for over 35 years.
Ingredients:

6 bacon strips, diced or (in place of bacon I use 1/2 cup olive oil)
3 pounds unpeeled medium red potatoes, cubed
2 medium onions, thinly sliced (optional)
1/2 cup cider vinegar (or red wine vinegar)
1/2 cup water
2-3 teaspoons sugar
3 tablespoons minced fresh parsley, divided (optional)
2-3 teaspoons Kosher salt
1-2 teaspoon prepared mustard (Gulden's)
1/4 teaspoon pepper
Adobo seasoning (optional)
(lately I also add a few stalks of celery rinsed and chopped, sometimes in place of onion)

In a pressure cooker, cook bacon (or olive oil) over medium heat until crisp; drain. Add potatoes and onions. In a bowl, combine the vinegar, water, sugar, 2 tablespoons of parsley, salt, mustard and pepper; pour over potatoes celery and onions.
Close cover securely; place pressure regulator on vent pipe. Bring cooker to full pressure over high heat. Reduce heat to medium and cook for 5 minutes. (Pressure regulator should maintain a slow steady rocking motion or release of steam; adjust heat if needed.) Remove from the heat.
Immediately cool according to manufacturer's directions until pressure is completely reduced. Just before serving, sprinkle with remaining parsley.

Mix the remaining super flavorful liquid in with the potatoes.
IMPORTANT: mix remaining liquid in with potatoes--that's where the flavor lives!
Refrigerate! The chilling brings out the flavor!