- With the rack in the middle position, preheat the oven to 180 °C (350 °F).
- Slice off the top of the head of garlic. Wrap in aluminum foil and bake for about 45 minutes. Let cool.
- Place the potatoes in a large pot and cover with lightly salted cold water. Bring to a boil and cook until tender. Drain, keeping a little cooking water to the side. Put the potatoes back on the heat for a few seconds to allow the cooking water to evaporate completely.
- Purée the potatoes into a coarse pulp using a masher. Press the bulb of garlic flesh out over the potatoes. Add the oil and beat with an electric mixer.
- If necessary, add some of the reserved cooking water to get a smooth purée. Season with salt and pepper.
- Perfect served with meat, poultry and fish.