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–+ servings

Classic Potato Gratin (Gratin Dauphinois)

Creamy, cheesy potato gratin baked until tender with a golden, bubbly top—an easy French-inspired side dish for weeknights or holidays.
Amanda
Prep Time 20 minutes
Cook Time 1 hour 20 minutes
Rest Time 10 minutes
Total Time 1 hour 50 minutes
Serving Size 8 servings

Equipment

  • Mandoline slicer or sharp knife
  • 9x13 inch baking dish
  • Saucepan
  • Whisk
  • Mixing bowl
  • Measuring cups and spoons
  • Cheese grater
  • Aluminum foil

Ingredients

  • 3 lb potatoes (Yukon Gold or russet) peeled if desired; sliced 1/8-inch thick
  • 3 tbsp unsalted butter plus more for greasing the dish
  • 3 tbsp all-purpose flour for thickening (roux)
  • 2 cups heavy cream
  • 1 cup whole milk
  • 2 cloves garlic minced
  • 2 cups Gruyère cheese shredded (or a mix of Gruyère and sharp cheddar)
  • 1 tsp kosher salt
  • 0.5 tsp black pepper
  • 1 tsp thyme dried (or 1 tbsp chopped fresh)

Instructions

  • Preheat oven to 375°F (190°C). Generously butter a 9x13-inch baking dish.
  • Slice the potatoes into thin rounds (about 1/8 inch). If prepping ahead, keep slices in cold water to prevent browning; drain and pat dry before layering.
  • Make the sauce: Melt butter in a saucepan over medium heat. Whisk in flour and cook 1 minute. Slowly whisk in heavy cream and milk until smooth.
  • Add minced garlic, salt, pepper, and thyme. Cook, stirring, until slightly thickened, about 3–4 minutes. Remove from heat.
  • Layer the gratin: Arrange 1/3 of the potatoes in the dish, slightly overlapping. Spoon 1/3 of the sauce over the potatoes, then sprinkle with 1/3 of the cheese. Repeat two more times, finishing with a generous layer of cheese on top.
  • Cover tightly with foil and bake 45 minutes. Remove foil and bake 30–35 minutes more, until the top is golden and bubbling and a knife slides through the potatoes easily.
  • Rest 10 minutes before serving so the sauce sets slightly. Slice and serve warm.

Notes

For the creamiest texture, use starchy potatoes like Yukon Gold or russet and slice evenly (a mandoline helps). Grate cheese fresh for the smoothest melt. Leftovers reheat best covered with foil at 350°F for 20–30 minutes.

Nutrition

Calories: 505kcal | Protein: 13g | Saturated Fat: 21g | Cholesterol: 115mg | Sodium: 520mg