In a large stock pot, add salt to water and boil peeled cubed potatoes for 20-25 minutes until they are fork tender. Drain the potatoes.
While potatoes are draining melt the butter in the stock pot. Once the butter is half way melted, add the potatoes back to the stock pot followed by sour cream, chives, minced garlic, and black pepper. Using a hand mixer, mix potatoes until smooth and creamy. Taste and decide if you want to add any additional salt and/or pepper. Top with additional chives and butter if desired and serve immediately.
Have leftovers? Freeze the mashed potatoes in a freezer zip lock. They will store for up to 3 months in the freezer. Perfect for a quick weeknight meal side dish!