500 grams yellow fleshed potatoes, peeled and quartered
1 sprig of thyme
1 cloves garlic, finely minced
3 tablespoons (45 grams) unsalted butter
1/2 cup (125 milliliters) 35% cream
325 grams Tomme d’Auvergne cheese, grated (or 200 grams Gruyère and 125 grams fresh mozzarella or fontina)
Place potatoes and thyme in a medium saucepan covered with four centimeters of water. Liberally salt water and bring to a boil over high heat. Cook until potatoes are fork tender, about 20 to 25 minutes.
Combine garlic, butter and heavy cream in a small saucepan and heat gently over low heat for 15 minutes.
Drain potatoes and discard the thyme. Pass potatoes through a ricer or a food mill, then add back into the saucepan. Add cream mixture and place over medium-low heat and stir the mixture together with a wooden spoon. Gradually add in grated cheese, a handful at a time, until mixture is stringy and thick. Season with salt.