Tender slices of potatoes layered with a creamy sauce with generous amount of cheddar...this is one of the greatest potato comfort food recipes of all time.
Preheat the oven to 400 F. Butter a 1 ½ quart baking dish or a 9x9 inch baking pan, or spray with nonstick spray.
In a medium bowl or a liquid measuring cup, combine the chicken broth, cream, mustard, thyme, salt, and pepper. Layer half the potatoes in the prepared baking dish. Sprinkle over half of the cheese and pour over half of the liquid mixture. Repeat with the rest of the potatoes, cheese, and liquid.
Cover the pan with foil and bake for 30 minutes. Remove the foil and continue to bake for another 45 minutes or so, until the potatoes are tender (a knife slides in easily) and the top is browned and crispy. Let stand for 15 minutes before serving.
Notes
You can make the gratin and bake it up to 2 days ahead of time and then reheat it in a preheated 350-degree oven for about 20 minutes until warmed through. Heat it covered with foil for about 10 minutes, then remove the foil for the rest of the reheating time.
If you don’t need a gratin to serve 6, make this anyway! It might sound strange, but a plate of leftover gratin heated up in the microwave is one of those breakfasts worth getting up early for. It can also last through the week, making weeknight dinners quick and easy to throw together.