Preheat the oven to 425F-degrees and line a metal baking sheet with parchment paper. For extra crispy potatoes, lightly spray the parchment with cooking spray.
Place the potatoes into a large pot of water and add 1/2 teaspoon of kosher salt. Boil the potatoes for 15-20 minutes until fork-tender. (The exact time will depend on the size of the potatoes). Drain well and let the steam evaporate for about 5 minutes.
1 1/2 lbs baby potatoes, 1/2 teaspoon kosher salt
Place the potatoes on the prepared baking sheet. Use a potato masher or the bottom of a glass to gently smash each potato until it's thin, but not broken.
Drizzle the flattened potatoes with olive oil, seasoning with flaky sea salt, pepper, and garlic powder.
2 tablespoons olive oil, 1/2 teaspoon flaky sea salt, 1/2 teaspoon black pepper, 1/2 teaspoon garlic powder
Put the tray into the oven and roast the potatoes for 20 minutes. Remove the tray, flip the potatoes, and roast for another 10-15 minutes until the potatoes are golden brown and the edges are crispy.
Add the mayo, onion powder, chives to the sour cream., then stir in the milk until the dip has the thickness you want.
1/2 cup sour cream, 2 tablespoons mayo, 1 tablespoon of milk, 1/2 teaspoon onion powder, 2 tablespoons fresh chives
Serve the potatoes hot with the sour cream on the side to keep them crispy.