Cheesy Potato Gratin Thyme (Printable)

A creamy, baked dish of layered potatoes and melted cheese infused with fresh thyme.

# What You'll Need:

→ Potatoes

01 - 3.3 lbs Yukon Gold or Russet potatoes, peeled and thinly sliced

→ Dairy

02 - 2 cups heavy cream
03 - 1 cup whole milk
04 - 2 cups shredded Gruyère cheese
05 - 1 cup grated Parmesan cheese
06 - 2 tbsp unsalted butter, plus extra for greasing

→ Aromatics & Herbs

07 - 2 cloves garlic, minced
08 - 2 tbsp fresh thyme leaves, plus additional for garnish

→ Seasonings

09 - 1 tsp salt
10 - ½ tsp freshly ground black pepper
11 - Pinch of freshly grated nutmeg (optional)

# How To Make:

01 - Preheat oven to 375°F. Butter a 9 x 13-inch baking dish thoroughly.
02 - In a saucepan over medium heat, combine heavy cream, whole milk, minced garlic, thyme leaves, salt, pepper, and nutmeg if using. Warm gently until steaming; remove from heat.
03 - Arrange half of the sliced potatoes evenly in the prepared baking dish. Sprinkle with half the Gruyère and Parmesan cheeses.
04 - Pour half of the warm cream mixture over the layered potatoes and cheese.
05 - Add remaining sliced potatoes over the first layer, then top with the remaining Gruyère and Parmesan cheeses.
06 - Pour the remaining cream mixture evenly over the top. Dot the surface with unsalted butter.
07 - Cover the dish with aluminum foil and bake for 40 minutes.
08 - Remove the foil and bake an additional 20 minutes, or until the top turns golden brown and potatoes are tender.
09 - Allow gratin to rest for 10 minutes before serving. Garnish with fresh thyme leaves.

# Expert Tips:

01 -
  • It looks like you spent hours in the kitchen, but most of the work happens in the oven while you attend to other things
  • The combination of Gruyère and Parmesan creates this deeply savory richness that tastes like a restaurant secret
  • It's naturally vegetarian but elegant enough to stand alongside any main course at your finest meals
02 -
  • The most common mistake is slicing the potatoes too thick. You want them thin enough that they cook through in an hour but not so thin they fall apart. A mandoline is your best friend here, but a sharp knife works too
  • Don't skip the resting step at the end. Those 10 minutes let the cream set slightly and make the gratin much easier to serve in neat portions
  • If your top is browning too fast before the potatoes are tender, your oven might run hot or the cream-to-potato ratio might be off. Cover it again with foil and give it more time
03 -
  • Slice your potatoes uniformly so they cook at the same rate. A mandoline makes this foolproof and takes the guesswork out of thickness
  • Infusing the cream with garlic and thyme while it's still cold, then heating it, extracts flavors more gently than dropping them into hot liquid
  • The key to a crispy golden top is making sure you uncover the dish in the final phase of baking. That direct oven heat is what creates the beautiful color and slight crust on top

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