Cook potatoes in salted water until fork-tender (12–15 minutes). Drain.
Place potatoes on a baking sheet, gently smash with a fork.
Drizzle with olive oil, season, and roast at 425°F (220°C) for 20–25 minutes until crispy.
Fry bacon until crispy, then crumble.
In a bowl, mix mayo, sour cream, mustard, lemon juice, garlic powder, salt, and pepper.
Add roasted potatoes to a large bowl. Toss gently with dressing, bacon, green onions, and dill.
Serve warm or chilled.
