Peel the garlic cloves and place in a small saucepan with the oil.
Bring the oil to a simmer over a medium heat then lower the heat and cook the garlic for 15 minutes.
Peel the potatoes and cut them into cubes around 1 centimetre or half an inch.
Place the potatoes in a large saucepan and cover with water. Add the lid and cook over a medium high heat for 10 to 15 minutes until the potatoes are tender.
Drain the potatoes in a colander then return to the saucepan to keep warm.
Take the rosemary needles off the stem and chop finely. Mash the garlic with a knife.
Add the garlic confit, butter, rosemary to the potatoes.
Mash the potatoes thoroughly, adding the milk as needed.
Season the potatoes to taste and grate in some nutmeg for extra flavour.