Creamy Potato Gratin Thyme (Printable version)
Thin potato slices layered with creamy sauce and fragrant thyme, baked golden and bubbling for a savory delight.
# What You'll Need:
→ Vegetables
01 - 3.3 lbs Yukon Gold or Russet potatoes, peeled and thinly sliced (1/16 inch)
02 - 1 medium yellow onion, thinly sliced (optional)
→ Dairy
03 - 1 2/3 cups heavy cream
04 - 3/4 cup plus 2 tablespoons whole milk
05 - 1/2 cup grated Gruyère cheese, plus extra for topping
06 - 1/3 cup grated Parmesan cheese
07 - 2 tablespoons unsalted butter, plus extra for greasing
→ Herbs & Seasoning
08 - 2 to 3 sprigs fresh thyme leaves, plus extra for garnish
09 - 2 cloves garlic, minced
10 - 1/4 teaspoon ground nutmeg
11 - 1 teaspoon fine sea salt
12 - 1/2 teaspoon freshly ground black pepper
# Directions:
01 - Preheat oven to 350°F. Generously butter a 2-quart gratin or casserole dish.
02 - In a saucepan, combine heavy cream, milk, garlic, nutmeg, salt, pepper, and thyme leaves. Warm gently over medium heat until steaming but not boiling, then remove from heat.
03 - Arrange half of the potato slices in overlapping layers in the prepared dish. Top evenly with half the onion slices (if using), half the Gruyère, and half the Parmesan cheese.
04 - Pour half of the warm cream mixture evenly over the layered potatoes and cheese.
05 - Repeat layering remaining potatoes, onions, Gruyère, and Parmesan. Gently press down to smooth the layers.
06 - Dot the surface with butter and sprinkle additional Gruyère cheese and a few thyme leaves.
07 - Cover the dish tightly with aluminum foil and bake for 40 minutes.
08 - Remove foil and bake an additional 20 minutes, or until golden brown and bubbling.
09 - Let the gratin rest for 10 minutes before serving. Garnish with fresh thyme leaves.
# Expert advice:
01 -
- The edges turn crispy and caramelized while the center stays impossibly creamy and tender.
- It looks impressive enough for guests but forgiving enough for a weeknight once you get the rhythm down.
- Thyme and nutmeg add a quiet warmth that makes the whole dish feel like a hug.
02 -
- Slicing the potatoes evenly is critical. I ruined my first gratin because some slices were thick and stayed crunchy while others turned to mush.
- Don't skip the resting time. Cutting into it too soon means the cream runs everywhere and you lose that beautiful layered structure.
03 -
- Use a mandoline with a hand guard. I still have a scar from the day I got careless.
- Press down on the layers halfway through assembly to help the cream distribute evenly and eliminate air pockets.