Place in a large pot, cover with cold water by 1 inch.
Bring to a boil, then simmer until fork-tender, 15-20 minutes.
Warm milk and melt butter together until steamy, not boiling.
Drain potatoes well; return to the hot pot over low heat 1 minute.
Mash potatoes. Gradually pour in warm milk-butter mixture.
Stir in sour cream, salt, pepper, and garlic powder until creamy.
Taste and adjust seasoning. Garnish with chives and serve hot.
Notes
Variation: Swap sour cream with 3 oz softened cream cheese, or fold in roasted garlic or shredded cheddar. Make-ahead: Keep warm in a slow cooker on Low with a splash of milk, or refrigerate up to 4 days and reheat gently with more milk.This recipe is an original creation inspired by classic Creamy Mashed Potatoes Made Easy flavors. All ingredient ratios and instructions are independently developed.