Ingredients

• 3 lb. 

  mixed potatoes, such as russets and Yukon golds, peeled, cut into 1" pieces

• Kosher salt

• 1/2 c. 

  whole milk

• 3/4 c. 

  (1 1/2 sticks) plus 2 tbsp. unsalted butter

• 1/2 c. 

  sour cream, room temperature

• Freshly ground black pepper

• Chopped fresh parsley, for serving

Description

1. Step 1In a large pot, cover potatoes with water and add a generous pinch of salt. Bring to a boil and cook until softened, 15 to 20 minutes.
2. Step 2Drain and return potatoes to pot. Using a potato masher or ricer, mash potatoes until smooth.
3. Step 3While potatoes cook, in a small saucepan over medium-low heat, cook milk and 3/4 cup butter, stirring occasionally, until butter is melted and mixture is warmed through.
4. Step 4Pour milk mixture over potatoes and stir until combined and creamy. Add sour cream and stir until combined; generously season with salt and pepper. 
5. Step 5Transfer potatoes to a serving bowl. Top with remaining 2 tablespoons butter; season with more pepper. Top with parsley.