This Roasted Garlic Potatoes au Gratin is rich, creamy, and packed with layers of cheesy comfort. I roast a whole head of garlic until it’s golden and buttery, then blend it into a velvety cream sauce that hugs every slice of potato. It’s indulgent, satisfying, and just the kind of side dish I love to make for cozy dinners or holiday spreads.
Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
8–9 medium potatoes (about 2½ lbs / 1.2 kg), thinly sliced
1 head of garlic (top trimmed to expose cloves)
1 tablespoon olive oil
¼ cup whole milk
1 cup heavy cream
1 tablespoon unsalted butter (plus extra for greasing)
Pinch of nutmeg
1 teaspoon fresh thyme leaves (or ⅓ tsp dried thyme)
Salt and black pepper, to taste
½ cup grated Parmesan cheese (divided)
2 cups shredded Gruyère or mozzarella cheese
Fresh chives, for garnish (optional)
Directions
Roast the garlic: I preheat the oven to 350°F (180°C), drizzle the head of garlic with olive oil, sprinkle with salt, and wrap it in foil. It roasts for about 30 minutes until soft and golden.
Prepare the pan: I grease a 9×13-inch (23×33 cm) baking dish with butter.
Slice the potatoes: I peel and thinly slice the potatoes, using a mandoline for evenness, and arrange the slices vertically in the dish.
Make the sauce: In a saucepan, I combine cream, milk, butter, thyme, nutmeg, half the Parmesan, salt, and pepper. I warm it over medium heat until everything is melted and steamy—never boiling.
Add roasted garlic: Once the garlic is soft, I squeeze the cloves out, mash them into a paste, and whisk it into the warm cream mixture.
Assemble: I pour the sauce over the potatoes, letting it seep between all the layers.
Bake covered: I cover the dish with foil and bake for 40 minutes.
Add cheese and finish baking: After removing the foil, I top everything with Gruyère and the remaining Parmesan, then bake uncovered for another 30 minutes, until bubbly and golden brown.
Serve: I let it rest for 10 minutes so the sauce settles. Chives on top are a nice touch if I have them.
Servings and timing
Servings: 6–8
Prep Time: 20 minutes
Cook Time: 1 hour 10 minutes
Total Time: 1 hour 30 minutes
Variations
I like switching things up depending on the occasion:
Use Yukon Gold or Russet potatoes for the best creamy texture.
Swap Gruyère with sharp white cheddar for a bolder flavor.
Add a layer of caramelized onions or crispy bacon for depth.
Mix in sautéed mushrooms or spinach for a veggie boost.
For a lighter version, I sometimes replace half the cream with whole milk.
Storage/Reheating
To store leftovers, I transfer the gratin into an airtight container or cover the baking dish with foil. It keeps in the fridge for up to 4 days. When I reheat it, I cover it with foil and warm it in a 350°F (180°C) oven for 20–25 minutes until heated through. A quick microwave reheat works too, but I prefer the oven for the best texture. I avoid freezing it because the cream sauce can separate.
FAQs
How do I keep the potatoes from turning gray after slicing?
I usually slice the potatoes just before assembling the dish. But if I prep ahead, I keep the slices submerged in cold water to prevent discoloration. I drain and pat them dry before layering.
Can I use pre-minced garlic instead of roasting a whole head?
Technically yes, but I don’t recommend it. Roasting a whole garlic head gives a sweet, mellow flavor that minced raw garlic just can’t match.
What’s the best type of potato for au gratin?
I like Russet potatoes for their starchiness, which helps thicken the sauce, or Yukon Golds for a naturally buttery taste. I avoid waxy potatoes like red or fingerlings—they don’t get as tender.
Can I make this recipe dairy-free?
I haven’t tried it dairy-free, but I imagine using a plant-based cream and cheese alternative could work. The flavor and texture will be different, though, so I’d test it before serving to guests.
How far in advance can I make this?
I often assemble the whole dish a day ahead, cover it tightly, and refrigerate it. When I’m ready to bake, I let it sit at room temperature for 30 minutes before popping it in the oven.
Conclusion
This Roasted Garlic Potatoes au Gratin is one of my favorite side dishes to make when I want something cozy, elegant, and full of flavor. It’s simple enough for a weeknight but impressive enough for a holiday table. Between the roasted garlic, creamy sauce, and golden cheesy top, it’s hard not to go back for seconds.
Recipe:
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Roasted Garlic Potatoes au Gratin
- Total Time: 1 hour 30 minutes
- Yield: 6–8 servings
- Diet: Vegetarian
Description
This Roasted Garlic Potatoes au Gratin is a rich, creamy, and cheesy side dish made with layers of thinly sliced potatoes, roasted garlic, and a velvety cream sauce. It’s perfect for cozy dinners or holiday gatherings, delivering deep flavor and indulgent comfort in every bite.
Ingredients
8–9 medium potatoes (about 2½ lbs / 1.2 kg), thinly sliced
1 head of garlic (top trimmed to expose cloves)
1 tablespoon olive oil
1 cup heavy cream
¼ cup whole milk
1 tablespoon unsalted butter (plus extra for greasing)
1 teaspoon fresh thyme leaves (or ⅓ tsp dried thyme)
Pinch of nutmeg
Salt and black pepper, to taste
½ cup grated Parmesan cheese (divided)
2 cups shredded Gruyère or mozzarella cheese
Fresh chives, for garnish (optional)
Instructions
- Preheat oven to 350°F (180°C). Drizzle the head of garlic with olive oil, sprinkle with salt, wrap in foil, and roast for about 30 minutes until soft and golden.
- Grease a 9×13-inch (23×33 cm) baking dish with butter.
- Peel and thinly slice the potatoes using a mandoline for evenness. Arrange the slices vertically in the prepared baking dish.
- In a saucepan, combine the cream, milk, butter, thyme, nutmeg, half the Parmesan, salt, and pepper. Warm over medium heat until melted and steamy, but not boiling.
- Squeeze the roasted garlic cloves out of the skin, mash into a paste, and whisk into the warm cream mixture.
- Pour the sauce evenly over the potatoes, allowing it to seep between layers.
- Cover the dish with foil and bake for 40 minutes.
- Remove foil, top with Gruyère and remaining Parmesan, and bake uncovered for another 30 minutes until golden and bubbly.
- Let rest for 10 minutes before serving. Garnish with fresh chives if desired.
Notes
Use Yukon Gold or Russet potatoes for the creamiest texture.
Swap Gruyère with white cheddar for a sharper flavor.
Add caramelized onions or crispy bacon for extra depth.
Include sautéed mushrooms or spinach for a veggie variation.
Replace half the cream with whole milk for a lighter option.
Store leftovers in an airtight container for up to 4 days in the fridge.
Reheat in the oven at 350°F (180°C) for 20–25 minutes, covered with foil.
Do not freeze; the cream sauce may separate.
- Prep Time: 20 minutes
- Cook Time: 1 hour 10 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: French
Nutrition
- Serving Size: 1 serving (approx. 1/8 of dish)
- Calories: 320
- Sugar: 2g
- Sodium: 350mg
- Fat: 22g
- Saturated Fat: 13g
- Unsaturated Fat: 7g
- Trans Fat: 0g
- Carbohydrates: 22g
- Fiber: 2g
- Protein: 9g
- Cholesterol: 60mg
