Preheat your oven to 400°F (200°C). Slice the top off the head of garlic, drizzle with olive oil, wrap in foil, and roast for 40-45 minutes.

While the garlic roasts, peel and chop the potatoes into 1-2 inch chunks, then add to a large pot of cold water.

Bring the water to a boil over high heat, reduce to medium, and cook the potatoes for about 20 minutes until fork-tender. Drain them and return to the hot pot.

Squeeze the roasted garlic from its skins into the pot with the drained potatoes.

Mash the potatoes and garlic together until smooth and fluffy, avoiding an electric mixer.

Add the butter, heavy cream, and milk to the mashed potatoes, stirring until well combined. Adjust the consistency as needed.

Season with salt and black pepper to taste, mixing well.

Optionally garnish with freshly chopped chives before serving.