Potato Gratin

Directions

1. 1
   Preheat the oven to 375F.
2. 2
   Butter a 14-inch oval gratin dish with 1 tablespoon of the butter.
3. 3
   Put the cream, stock, bay leaf, and salt in a medium pot, and stir to combine.
4. 4
   Bring the mixture to a simmer, reduce the heat to low, and let steep while you prepare the potatoes.
5. 5
   Peel the potatoes.
6. 6
   Use a mandoline slicer or a knife to cut the potatoes into 1/8-inch-thick slices.
7. 7
   Neatly layer the slices in the gratin dish, overlapping slightly, like shingles on a rooftop, making 3 or 4 layers.
8. 8
   Its important to slice the potatoes and immediately assemble the gratin, before the potatoes oxidize and turn brown.
9. 9
   Avoid putting the potatoes in water.
10. 10
    You dont want to rinse off any of the potato starchthe starch is essential for a rich, creamy gratin.
11. 11
    Remove the bay leaf from the cream mixture and discard.
12. 12
    Gently pour the mixture over the potatoes.
13. 13
    The liquid level should be just below the surface of the potatoes; when you gently press the potatoes down with a spatula, the cream mixture should spill over the top layer of potatoes.
14. 14
    Dot the remaining 2 tablespoons butter on top, and cover tightly with foil.
15. 15
    Bake until the potatoes are almost tender when pierced with a small, sharp knife, about 35 minutes.
16. 16
    Increase the oven temperature to 400F.
17. 17
    Press the potatoes down with a spatula to an even thickness, allowing the creamy juices to baste the top.
18. 18
    Sprinkle the thyme and black pepper on top.
19. 19
    Continue to bake, uncovered, pressing the potatoes down with a spatula to baste periodically, until the gratin is nicely browned, about 30 minutes.
20. 20
    (Its okay if the gratin is a little loose and creamy at this point.)
21. 21
    Remove from the oven and let stand for 5 minutes before serving, to allow the gratin to settle and absorb some of the cream.