Roasted Garlic Potatoes au Gratin – Creamy, Cheesy Comfort Food

Few side dishes capture the heart of comfort cooking like Roasted Garlic Potatoes au Gratin. Rich, bubbling, and irresistibly creamy, this timeless French-inspired casserole transforms simple ingredients into something luxurious.

Layered thin-sliced potatoes are blanketed in a velvety garlic-infused cream sauce and baked until golden, with crispy edges and a soft, melt-in-your-mouth center. Roasted garlic adds a mellow, nutty sweetness that elevates the flavor from basic to memorable—making it a perfect side dish for everything from holiday dinners to cozy weeknight meals.

Whether you’re serving it with a holiday roast or a crisp green salad, this dish is pure comfort on a plate.

Ingredients Overview

Potatoes

• Yukon Gold or Russet potatoes are best for gratin. Yukon Golds offer a creamy texture and buttery flavor, while Russets absorb cream well and break down slightly, creating an ultra-soft bite.

• Peel if you prefer a smooth finish, or leave skins on for a rustic look.

Roasted Garlic

• Roasting garlic turns its sharp bite into a caramelized, nutty flavor. One whole head of garlic is used here—slow-roasted until soft and golden.

• You can roast garlic ahead of time and store it in the fridge for up to a week.

Heavy Cream & Milk

• A mix of heavy cream and whole milk gives a luxurious texture without being overly heavy.

• You can use all cream for indulgence or lighten with 2% milk if needed.

Cheese

• Gruyère cheese adds rich, nutty flavor and melts beautifully.

• Combine with sharp white cheddar for added depth.

• Other options: Fontina, Comté, or a mild Swiss.

Butter

• Unsalted butter helps sauté the garlic and onions (if using), and adds flavor to the cream base.

Nutmeg & Thyme

• Just a pinch of nutmeg adds subtle warmth and aroma.

• Fresh thyme leaves bring a savory herbal note. Dried thyme works in a pinch.

Salt & Pepper

• Essential for seasoning the potatoes evenly. Use kosher salt and freshly ground black pepper.

Step-by-Step Instructions

1. Roast the garlic
   Preheat oven to 400°F (200°C). Slice the top off a head of garlic to expose cloves. Drizzle with olive oil, wrap in foil, and roast for 40 minutes until soft and golden. Let cool, then squeeze out the cloves and mash into a paste.

2. Prep potatoes
   Slice potatoes thinly (about ⅛ inch) using a mandoline or sharp knife for even cooking. Place slices in a bowl of cold water to prevent browning and remove excess starch. Drain and pat dry before assembling.

3. Make the cream sauce
   In a saucepan, melt butter over medium heat. Add mashed roasted garlic and sauté briefly. Pour in the cream and milk, add thyme, nutmeg, salt, and pepper. Heat until just simmering, then remove from heat.

4. Layer the gratin
   Preheat oven to 375°F (190°C). Grease a 9×13-inch baking dish. Arrange half of the potato slices in overlapping layers. Pour half the cream mixture over, sprinkle with half the cheese. Repeat with remaining potatoes, cream, and cheese.

5. Bake covered
   Cover dish with foil and bake for 40 minutes until potatoes begin to soften.

6. Bake uncovered
   Remove foil and continue baking 25–30 minutes until golden brown on top and bubbling around the edges. A knife should slide easily through the layers.

7. Rest before serving
   Let gratin sit for 10–15 minutes before serving. This helps the sauce thicken and the flavors settle.

Tips, Variations & Substitutions

• Make ahead: Assemble the dish a day in advance, cover, and refrigerate. Bake just before serving.

• Add caramelized onions or sautéed leeks between layers for added sweetness and depth.

• For a crispier topping, sprinkle with panko breadcrumbs tossed in butter before the final bake.

• Want a vegetarian main dish? Add thin slices of roasted butternut squash or mushrooms between the layers.

• For a lighter version, use half-and-half or substitute some of the cream with unsweetened almond milk and use less cheese.

Serving Ideas & Occasions

Roasted Garlic Potatoes au Gratin is a hearty, rich side dish that pairs beautifully with:

• Prime rib, roast beef, or baked ham

• Herb-crusted lamb chops or baked chicken

• A fresh green salad with vinaigrette to cut the richness

It’s an ideal dish for:

• Holiday dinners like Christmas or Easter

• Sunday family meals

• Dinner parties or potlucks

• Cold weather comfort meals

Its golden crust and aromatic garlic make it both impressive and deeply satisfying.

Nutritional & Health Notes

This gratin is high in flavor—and calories—thanks to the cream and cheese, so it’s best enjoyed in moderation as part of a balanced meal.

• Protein: The cheese contributes to the protein content.

• Carbohydrates: Potatoes are naturally high in carbs, providing energy.

• Calcium: Thanks to the cheese and milk, this dish offers a good source of calcium.

For a lighter approach:

• Reduce cheese by 25%

• Swap part of the cream with whole milk or vegetable broth

• Try sweet potatoes for a lower glycemic alternative

FAQs

Q1: Can I use pre-shredded cheese?

A1: It’s best to grate cheese yourself. Pre-shredded cheese often contains anti-caking agents that can affect the smoothness of the sauce and melting consistency.

Q2: How thin should the potato slices be?

A2: Aim for about ⅛-inch thickness. Uniform slices cook evenly and absorb the cream properly. Use a mandoline for best results.

Q3: Can I freeze potatoes au gratin?

A3: It’s not ideal to freeze before baking as raw potatoes can discolor and become grainy. However, you can freeze fully baked and cooled gratin in portions. Reheat gently in the oven.

Q4: How do I make this dish ahead of time?

A4: Assemble the entire dish (without baking), cover tightly with foil, and refrigerate up to 24 hours. Let it sit at room temp for 30 minutes before baking as directed.

Q5: Can I add other herbs or spices?

A5: Yes. Fresh rosemary, sage, or a hint of smoked paprika can complement the garlic well. Just avoid overpowering the roasted garlic’s sweetness.

Q6: What’s the difference between scalloped potatoes and gratin?

A6: Gratin typically includes cheese and a browned top, while scalloped potatoes are usually just layered with a milk-based sauce, and sometimes cooked entirely on the stovetop.

Q7: Is there a low-carb version?

A7: Yes! Try thinly sliced turnips, cauliflower, or rutabaga in place of potatoes. Use a lighter cream sauce made with cauliflower purée and almond milk to reduce carbs.

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