Creamy Yukon Gold Potato Gratin with Gruyère and Thyme

Why You’ll Love This Recipe

• Comforting, restaurant-quality flavor: silky potatoes, infused garlic-thyme cream, and nutty Gruyère.
• Approachable techniques with make-ahead options for stress-free hosting.
• Beautiful, deeply golden crust with tender, sliceable layers underneath.
• Scales easily for holidays and pairs with everything from roast chicken to seared salmon.

Grocery List

• Produce: 3 lb Yukon Gold potatoes, 1 head garlic, fresh thyme, 1 bay leaf (optional)
• Dairy: Heavy cream, whole milk, Gruyère, Parmesan (optional), unsalted butter
• Pantry: Kosher salt, black pepper, ground nutmeg, aluminum foil

Full Ingredients

For the cream infusion

• 2 cups heavy cream
• 1 cup whole milk
• 4 garlic cloves, smashed
• 6 fresh thyme sprigs
• 1 bay leaf (optional)
• 2 tsp kosher salt
• 1/2 tsp freshly ground black pepper
• 1/8 tsp ground nutmeg

For the gratin assembly

• 3 lb Yukon Gold potatoes, peeled and sliced 1/8 inch (about 1.4 kg)
• 8 oz Gruyère, shredded (about 2 cups; 225 g)
• 1/2 cup finely grated Parmesan (optional)
• 2 tbsp unsalted butter, divided (1 tbsp to grease dish; 1 tbsp, cold, cut into small cubes to dot the top)
• 1 garlic clove, halved (to rub the dish)

Optional garnish

• 1 tsp fresh thyme leaves, chopped

Step-by-Step Instructions

Step 1: Preheat and prepare the baking dish

Heat the oven to 375°F (190°C) with a rack in the center. Rub a 9×13-inch (3-quart) baking dish all over with the cut side of a halved garlic clove, then generously butter the dish (about 1 tbsp). This adds subtle garlic aroma and prevents sticking.

Step 2: Slice potatoes and grate the cheese

Peel the Yukon Golds and slice them to 1/8 inch (3 mm) thickness using a mandoline or a very sharp knife. Keep slices in neat stacks; do not rinse—natural starch helps thicken the cream. Shred the Gruyère on the large holes of a box grater. If using Parmesan, finely grate it and set aside.

Step 3: Infuse and season the cream

In a medium saucepan, combine the heavy cream, milk, smashed garlic, thyme sprigs, and bay leaf (if using). Bring to a gentle simmer over medium heat, 3–5 minutes; do not boil. Stir in the salt, pepper, and nutmeg. Remove from heat, cover, and let steep 10 minutes. Strain the hot cream into a measuring jug, pressing on solids to extract flavor. You should have about 3 cups; if short, top up with a splash of milk.

Step 4: Layer the gratin

Arrange a snug, slightly overlapping layer of potatoes in the prepared dish. Ladle over about 3/4 cup hot cream to moisten. Sprinkle a scant 2/3 cup Gruyère evenly across. Repeat to make 3–4 layers total, ending with potatoes. Press down gently with your palms to level and help the cream rise around the slices.

Step 5: Bake covered until tender

Cover the dish tightly with foil (tip: add a sheet of parchment under the foil to prevent sticking). Bake for 40 minutes. The potatoes should be starting to soften, and bubbles will form at the edges.

Step 6: Uncover, brown, and finish

Remove foil. Scatter the remaining Gruyère and the Parmesan (if using) evenly over the top. Dot with the remaining 1 tbsp cold butter. Return to the oven and bake uncovered 25–35 minutes, until the top is deeply golden and a knife slides through the center with no resistance. For extra color, broil 1–2 minutes, watching closely.

Step 7: Rest and serve

Let the gratin rest 15 minutes to set the layers for clean slices. Garnish with chopped fresh thyme. Serve warm, scooped or cut into squares.

Pro Tips

• Consistency matters: 1/8 inch slices cook evenly and stack into neat, creamy layers.
• Do not rinse sliced potatoes—their starch thickens the sauce naturally.
• If the top browns too fast, tent loosely with foil; if it is pale near the end, use a brief broil.
• For ultra-silky results, use all heavy cream; for lighter, swap the milk-to-cream ratio (but keep at least half cream to prevent curdling).
• Strain the infused cream to avoid garlic pieces that can over-brown on top.

Variations

• Classic Dauphinoise: Skip the cheese. Increase cream to 2 1/2 cups, add an extra garlic clove, and a pinch of white pepper.
• Gruyère + Comté Blend: Use half Gruyère, half Comté for an extra-nutty French bistro vibe.
• Bacon-Onion: Fold 1 cup cooked lardons and 1 cup deeply caramelized onions between layers for a smoky-sweet twist.

Storage & Make-Ahead

Assemble up to 24 hours ahead: layer potatoes with the hot infused cream, cover tightly, and refrigerate; bake straight from the fridge, adding 10–15 minutes to the covered bake time. Par-bake method: bake covered for 35–40 minutes, cool, cover, and refrigerate up to 2 days; finish uncovered with cheese 30–35 minutes. Leftovers keep 3–4 days refrigerated; reheat covered at 350°F (175°C) for 20–25 minutes, then uncover to re-crisp. Freeze fully baked gratin up to 2 months; thaw overnight and reheat as above.

Nutrition (per serving)

Approximate: 520 calories; 31 g carbohydrates; 36–38 g fat; 15–16 g protein; 650 mg sodium. Values will vary with cheese brand, salt, and portion size.