Roasted Garlic Potatoes Gratin

A rich and comforting potato gratin layered with tender potatoes, roasted garlic, cream, and plenty of melted cheese. The top becomes beautifully golden and crisp while the inside stays creamy and tender.

Ingredients

For the roasted garlic:

• 1 whole garlic bulb
• 1 teaspoon olive oil
• Pinch of salt

For the gratin:

• 2½ lbs (1.1 kg) Yukon Gold or russet potatoes
• 2 tablespoons butter, for greasing
• 1½ cups heavy cream
• ½ cup whole milk
• 6 oz (170 g) Gruyère cheese, freshly grated
• ½ cup Parmesan cheese, freshly grated
• 1 teaspoon fresh thyme leaves
• ½ teaspoon dried thyme
• ½ teaspoon black pepper
• ¾ teaspoon salt, or to taste
• ¼ teaspoon nutmeg, optional
• 1 tablespoon fresh parsley, chopped

Directions

1. Roast the garlic:
   Preheat the oven to 400°F (200°C).
2. Cut the top off the garlic bulb to expose the cloves. Place it on a small piece of foil, drizzle with olive oil, and sprinkle with a pinch of salt.
3. Wrap the garlic tightly in foil and place it on a baking sheet.
4. Roast for 35–45 minutes, until the cloves are very soft and golden.
5. Allow the garlic to cool enough to handle. Squeeze the roasted cloves out of their skins and mash them into a smooth paste.
6. Prepare the potatoes:
   Reduce the oven temperature to 375°F (190°C).
7. Peel the potatoes if desired. Slice them very thinly, about ⅛ inch (3 mm) thick. A mandoline makes this easier and creates evenly cooked layers.
8. Do not soak the potatoes after slicing. The natural starch helps thicken the gratin.
9. Prepare the cream mixture:
   In a saucepan over medium-low heat, combine heavy cream, milk, roasted garlic paste, dried thyme, black pepper, salt, and optional nutmeg.
10. Warm for 3–4 minutes, stirring occasionally. Do not bring the mixture to a hard boil.
11. Assemble:
    Generously butter a 9×13-inch (23×33 cm) baking dish.
12. Arrange one layer of sliced potatoes across the bottom, slightly overlapping each slice.
13. Sprinkle a small amount of Gruyère and Parmesan over the potatoes.
14. Repeat the layers until all the potatoes are used.
15. Slowly pour the warm garlic cream mixture evenly over the potatoes.
16. Press the potatoes down gently with a spatula so the cream reaches between the layers.
17. Sprinkle the remaining Gruyère and Parmesan over the top.
18. Add fresh thyme leaves.
19. Bake:
    Cover the dish tightly with foil and bake for 45 minutes.
20. Remove the foil and continue baking for another 25–35 minutes, until the potatoes are completely tender and the top is deeply golden and bubbling.
21. For an extra-crispy top, place the gratin under the broiler for 1–2 minutes, watching carefully.
22. Rest:
    Remove from the oven and let the gratin rest for 15–20 minutes before serving. This allows the creamy layers to set slightly and makes serving easier.
23. Garnish with fresh parsley and a few thyme leaves before serving.

Tips for the best potato gratin

• Slice the potatoes as evenly and thinly as possible.
• Yukon Gold potatoes create an especially creamy texture.
• Don’t rinse the sliced potatoes; their starch helps thicken the sauce.
• Freshly grated cheese melts more smoothly than pre-shredded cheese.
• Don’t rush the resting time after baking.
• If the top browns too quickly, loosely cover it with foil.
• For extra garlic flavor, mash two additional roasted garlic cloves into the cream mixture.
• Letting the cream mixture become very hot before pouring can cause uneven cooking, so keep it gently warmed.

Nut information

• This recipe contains no peanuts or tree nuts.
• Nutmeg is technically a seed rather than a tree nut, but it is optional and can be omitted.
• Check the labels of packaged cheeses and dairy products for allergen or cross-contact warnings.
• For a strict nut-free preparation, use ingredients specifically labeled according to your allergy requirements.

Nutrition estimate

Per serving, based on 8 servings:

• Calories: approximately 440
• Protein: 14 g
• Carbohydrates: 34 g
• Fat: 29 g
• Saturated fat: 18 g
• Fiber: 3 g
• Sugar: 3 g
• Sodium: approximately 520 mg

Q/S

Prep time: 20 minutes
Garlic roasting: 35–45 minutes
Gratin baking: 70–80 minutes
Resting time: 15–20 minutes
Total time: About 2–2½ hours
Servings: 8
Difficulty: Easy to moderate

Storage

Store leftovers covered in the refrigerator for up to 4 days. Reheat in a 350°F (175°C) oven until hot and bubbling. Individual portions can also be reheated in the microwave, although the top will be less crispy.