01 - Place the cubed potatoes in a large pot, cover with cold water, and stir in 1 tablespoon salt. Bring to a boil over high heat, then reduce the heat and simmer for 10 to 12 minutes until the potatoes are fork-tender. Drain well and let cool slightly.
02 - While potatoes are cooking, fry chopped beef bacon in a large skillet over medium heat until crisp. Transfer the bacon to a paper towel-lined plate to drain excess fat.
03 - In a large mixing bowl, whisk together sour cream, mayonnaise, Dijon mustard, and black pepper until smooth.
04 - Add the warm, drained potatoes to the bowl with the dressing. Gently fold to coat the potatoes evenly.
05 - Add the diced celery, sliced green onions, shredded cheddar cheese, chopped parsley, and most of the cooked beef bacon (set aside some for garnish). Mix gently until all components are well distributed.
06 - Adjust seasoning with additional salt and pepper as needed.
07 - Transfer salad to a large serving platter or bowl. Garnish with reserved green onions, remaining beef bacon, and extra parsley.
08 - Serve warm, at room temperature, or chilled according to preference.