In a large stock pot, combine cubed Yukon Gold potatoes with 1 tablespoon of salt and cover with cold water. Bring to a boil and cook until tender, about 12 to 16 minutes. Drain and set aside.

Preheat your oven to 400°F (200°C) and line a baking sheet with aluminum foil.

Toss the drained potatoes with olive oil, garlic powder, salt, and pepper in a large mixing bowl.

Spread the seasoned potatoes in a single layer on the prepared baking sheet and roast for about 30 minutes, tossing halfway through.

While roasting, prepare the dressing by combining sour cream, mayonnaise, scallions, dill, parsley, mustard, lemon juice, salt, and pepper until smooth.

Once the potatoes are roasted, let them cool slightly, then toss with the dressing just before serving.