Roast the garlic: Preheat oven to 400°F (200°C). Slice about 1/4 inch off the top of the garlic head to expose the tops of the cloves. Place on a square of foil, drizzle with 1 tsp olive oil (or a light drizzle of butter), wrap tightly and roast for 30–35 minutes until cloves are soft and golden. Let cool slightly.

Boil the potatoes: Place the potato chunks in a large pot and cover with cold water by about an inch. Add 1 tsp salt. Bring to a boil over high heat, then reduce to a simmer and cook until potatoes are very tender when pierced, about 15–20 minutes depending on size.

Drain and dry: Drain the potatoes well in a colander. Return them to the warm pot and place over low heat for 1–2 minutes to let excess moisture evaporate. This helps keep the mash fluffy, not watery.

Squeeze the roasted garlic: Once the garlic is cool enough to handle, squeeze the soft roasted cloves out of their skins into a small bowl. Mash with a fork to a paste.

Warm the dairy: In a small saucepan (or in the microwave), warm the butter, cream, and milk together until the butter is melted and the liquid is warm but not boiling. Warming helps the potatoes absorb the liquids better for a silky texture.

Mash: Mash the potatoes using a potato masher, ricer, or food mill to your desired consistency. For very creamy potatoes, push them through a ricer or use a hand mixer on low speed briefly (careful not to overwork).

Combine: Stir in the roasted garlic paste, warm dairy mixture, salt, and pepper. Taste and adjust seasoning. If the mash feels too stiff, add a splash more milk until you reach the texture you like.

Serve: Spoon into a serving bowl, dot with a little extra butter if desired and sprinkle with chopped chives or parsley. Serve warm.