1. Cover the potatoes and garlic with cold water and heat. Don’t start with hot water; the heat must be gradual.
2. Bring to boil. Once the water is boiling, let it simmer for 25 minutes. (Pro tip from Robuchon: “Prick a potato with the tip of a knife and try lifting it up. If it falls off, it’s cooked.”)
3. Peel the potatoes while still hot.
4. Press Potatoes and Garlic through ricer.
5. Cut the butter into lumps and mix it slowly into the potatoes over a low heat.
6. Add the cream slowly while mixing. Salt and Pepper to taste.
7. Pass the mash through a sieve, then spread into oven safe dish.