• Preheat the oven to 425℉.

Make the Potatoes:

• Place the potatoes on a large baking sheet and drizzle with the olive oil and add the salt and pepper. Toss to coat. Transfer to the oven and bake until golden brown and the skin is slightly crisp, 18 to 20 minutes.
• Using a potato masher or serving fork, smash each potato to about a 1/4-inch thickness. Return to the oven and bake until the edges are crispy, 8 to 10 more minutes.

Make the Sauce:

• Meanwhile, in a small saucepan, heat the vinegar over medium heat and bring it to a simmer. Cook, simmering, until it has been reduced to 1 tablespoon, 3 to 4 minutes. Remove from the heat and let cool.
• In a small bowl, combine the sour cream, olive oil, and garlic. When the vinegar has cool, stir that in.

Assemble:

• On a large dinner plate or serving platter, spoon half of the sour cream sauce on the bottom of the plate and spread and swoop to coat the bottom center of the plate.
• When the potatoes are crisp, transfer them onto the plate into a pretty pile of smashed potatoes. Dollop the remaining sour cream sauce on the top. Sprinkle with the grated sharp cheddar cheese, then the bacon, then the chives. Top with freshly ground black pepper and serve.