1
Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.
Dice potatoes into 1⁄2-inch pieces and place in a medium pot with enough salted water to cover by 2 inches. Bring to a boil and cook until tender, 10-12 minutes.
Reserve 1⁄2 cup potato cooking liquid (3⁄4 cup for 4 servings), then drain. Return potatoes to pot and mash with sour cream and 1 TBSP butter (2 TBSP for 4) until smooth and creamy, adding splashes of reserved potato cooking liquid as needed. Taste and season with salt and pepper.