Prep the potatoes: Peel (optional) and cut the potatoes into even 1½–2 inch chunks so they cook uniformly.

Cook the garlic: If roasting, slice the top off the head, drizzle with a little olive oil, wrap in foil and roast at 400°F (200°C) for 25–30 minutes until soft. If short on time, smash a few garlic cloves and simmer with the potatoes for about 10 minutes of the boiling time to soften the garlic flavor.

Boil the potatoes: Place cut potatoes in a pot and cover with cold salted water. Bring to a simmer and cook until fork-tender, about 15–18 minutes.

Drain and dry: Drain potatoes well and return them to the hot pot. Over low heat, stir for 30–60 seconds to evaporate excess moisture — this keeps mash from being watery.

Mash gently: Mash potatoes with a potato masher or ricer until mostly smooth. Avoid overworking to prevent gluey texture.

Add dairy and garlic: Fold in butter, roasted garlic (squeezed from skins) or softened garlic, warm cream, and sour cream if using. Stir until combined and creamy.

Melt in the cheese: Add the grated sharp cheddar a little at a time, stirring until fully melted and distributed. Season with salt and pepper to taste.

Finish and garnish: Transfer to a serving bowl, top with an extra pat of butter and sprinkle chopped chives or parsley. Serve immediately while hot.