- Preheat the oven to 180°C. Grease a large oven proof dish with about ½ tablespoon butter.
- Slice the potatoes very thinly – about 3mm thick; a mandoline works well for this.
- Combine in a large saucepan with the crushed garlic, the remaining 2½ tablespoons butter, the cream and the milk, the Kefalos Crème Fraîche, flour, thyme, nutmeg, 2½ teaspoons salt, and pepper to taste.
- Bring to a boil over medium-high heat and cook, stirring, until the mixture thickens slightly, 1 to 2 minutes.
- Stir in the chives and transfer the mixture to the prepared baking dish, shaking it to distribute the potatoes evenly.
- Bake, uncovered, until the potatoes are fork-tender; about 1 hour 5 minutes, occasionally spooning some of the liquid over the top.
- Let cool 10 minutes before serving