Peel and cube potatoes, place them in a large pot, cover with cold water by about an inch, and add 1 tablespoon of salt.

Bring the water to a boil, then simmer until the potatoes are very tender (about 15-20 minutes); drain well.

While potatoes boil, preheat oven to 400°F (200°C), cut off the top of the garlic head, drizzle with olive oil, and wrap in foil.

Roast for 30-40 minutes until soft and golden brown, then let cool slightly before squeezing out the cloves.

In a small saucepan, melt 1 stick of unsalted butter over medium heat, stirring until it foams and small brown bits appear at the bottom (5-7 minutes).

Remove the nutty, amber butter from heat immediately; optionally strain it through a fine-mesh sieve.

Return drained potatoes to the pot, add roasted garlic cloves, and mash until smooth using a potato masher, ricer, or stand mixer.

Warm the milk or cream, then pour it into the mashed potatoes along with a slow drizzle of brown butter, stirring until combined and creamy.

Season with salt and black pepper to taste, and if desired, stir in fresh chives or parsley.