2 1/4 lbs. Russet potatoes
1 clove of garlic, smashed
5 tablespoons butter
2 1/2 cups half and half
sea salt, to taste
fresh ground black pepper, to taste
1 cup shredded Gruyere
Heat oven to 300 degrees
Peel potatoes and slice very thin using a food processor or mandoline. Place potatoes in bowl cover with cold water. Swish potatoes around in bowl to remove excess starch. Drain and place potatoes in salad spinner to remove all excess water or dry with tea towel.
Rub a large shallow baking dish with the garlic clove, set clove a side and then butter dish.
Put the butter in a large pot with half and half and bring just to a boil. Add potatoes, season with salt and pepper, mince the garlic clove set aside from rubbing on baking dish and add to potatoes as well. Gently bring to a simmer and simmer 8 minutes.
Transfer to prepared dish, spread evenly and sprinkle with cheese and season with salt and pepper. Place baking dish on sheet baking to prevent any possible mess in the bottom of your oven.
Bake for 1 1/2 hours. Serve hot.