The Creamiest Homemade Au Gratin Potatoes
Few side dishes can match the creamy, cheesy decadence of Au Gratin Potatoes. Baked to golden perfection with layers of tender, thinly sliced russet potatoes and a dreamy blend of Gruyere, Parmesan, cream, garlic, and fresh thyme, this classic recipe is elegant enough for special occasions—but simple enough for weeknight meals.
Whether you’re hosting a holiday feast or just want to elevate your dinner plate, this dish delivers comfort and flavor in every bite. Bonus? It’s totally make-ahead friendly and pairs beautifully with everything from roasted chicken to prime rib.
Why This Au Gratin Potato Recipe Stands Out
We stick with the traditional no-flour approach, letting the natural starch in russet potatoes thicken the sauce beautifully as it bakes. The result? A silky, luxurious texture that clings to every bite. For extra depth, we also caramelize diced yellow onions to balance the richness with a subtle sweetness.
Our blend of cheeses—Gruyere for meltability and tang, and Parmesan for that irresistible umami kick—makes this dish especially indulgent. And yes, fresh garlic and thyme take the flavor to the next level.
Step-by-Step: How to Make the Best Au Gratin Potatoes
- Caramelize the onions in butter for extra sweetness and depth. Add garlic and fresh thyme.
- Simmer cream and milk, then stir in Gruyere and Parmesan cheese slowly to create a velvety sauce.
- Slice your russet potatoes to ⅛-inch thin using a mandoline for best results.
- Layer it all: Potatoes, sauce, potatoes, sauce—repeat until your dish is filled.
- Bake covered at 350°F for 1 hour, then uncover and continue baking for 30 more minutes.
- Optional: Broil for 1-2 minutes to brown the top.
- Let it rest for 5–10 minutes before garnishing with chives and serving.
Make-Ahead Instructions
Want to prep ahead? Assemble and bake for 45 minutes. Cool completely, then refrigerate up to 2 days. When you’re ready to serve, bring it to room temperature for an hour, then bake covered at 350°F for 20 minutes, uncover, and bake another 30 minutes until bubbly and hot. Broil at the end for that golden finish.
Pro Tips for Perfect Au Gratin Potatoes
- Stick with Russet Potatoes: Their starch content is essential for a thick, creamy sauce. Yukon Golds are okay, but avoid waxy reds.
- Slice Super Thin: Aim for paper-thin, 1/8-inch slices so they cook evenly.
- Use a Mandoline: It’s the best tool for consistency, but always use the safety guard!
- Grate Cheese Fresh: Skip the pre-shredded stuff. Freshly grated cheese melts smoother and tastes better.
- Use Fresh Garlic: It really makes a difference compared to jarred varieties.
- Expect a Thin Sauce at First: It will thicken beautifully as it bakes and rests.
How to Store Leftovers
Store leftovers in an airtight container in the refrigerator for up to 5 days. While it’s possible to freeze, note that the texture may change a bit upon reheating. Reheat gently in the oven for best results.
Tools That Make It Easier
- Mandoline Slicer – For consistent, thin potato slices.
- 2.5 Quart Baking Dish – Corningware or a 9×13 casserole both work well.
- Box Cheese Grater – Better melting and flavor from freshly grated cheese.
- Garlic Peeler & Twister – Peel and mince garlic effortlessly.
Perfect Pairings to Try Next
- Garlic Butter Pasta
- Loaded Mashed Potatoes
- Cream of Mushroom Soup
- Olive Oil Bread Dip
- Crispy Baked Potato Slices
- Fluffy Dinner Rolls
Cheesy Au Gratin Potatoes Recipe
Ingredients:
- 1 small yellow onion, finely diced
- 3 tablespoons salted butter
- 4 cloves fresh garlic, minced
- 2 teaspoons fresh thyme leaves
- 2 cups heavy cream
- ½ cup milk
- 2 cups shredded Gruyere cheese
- ½ cup grated Parmesan cheese
- ¼ teaspoon salt
- ¼ teaspoon black pepper
- 2½ lbs. russet potatoes
- Chives, for garnish
Instructions:
- Preheat oven to 350°F.
- Microwave cream and milk for 1 minute. Set aside.
- In a pot, soften onions in butter for 10 minutes over medium heat. Lower heat and cook for 10–15 more minutes to caramelize. Add garlic and thyme.
- Remove from heat. Gradually add warmed cream/milk mixture. Return to medium-high heat and bring to a gentle boil.
- Remove from heat. Slowly stir in Gruyere and Parmesan until melted. Season with salt and pepper.
- Slice potatoes thin (⅛ inch) using a mandoline.
- In a greased baking dish, layer ⅓ of the potatoes, followed by ⅓ of the cheese sauce. Repeat until complete.
- Cover and bake for 1 hour. Uncover and bake 30 more minutes. Broil for extra browning if desired.
- Rest for 10 minutes. Garnish with chives and serve.
Frequently Asked Questions
Can I use a different cheese besides Gruyere?
Yes! While Gruyere offers a distinct, nutty flavor and melts beautifully, Fontina or white cheddar can also be used. For best results, combine with Parmesan for that classic sharpness.
What’s the difference between Au Gratin and Scalloped Potatoes?
Scalloped potatoes typically use a flour-based roux and sometimes omit cheese. Au Gratin potatoes, on the other hand, are layered with cheese and use cream for a richer texture.
Do I need to peel the potatoes?
It’s highly recommended to peel russet potatoes for a smoother texture and to allow the cream sauce to absorb evenly into the layers.
Can I prepare this in a slow cooker?
Yes, layer everything in a slow cooker and cook on low for about 5 hours. The top won’t brown, but the flavors remain just as creamy and rich.
What should I serve with Au Gratin Potatoes?
They go wonderfully with roast chicken, ham, grilled steak, pork chops, or even as a hearty side for a vegetarian feast.
Reference Links
AllRecipes – What Are Au Gratin Potatoes?
Serious Eats – The Science of Potatoes Au Gratin
The Kitchn – How to Make the Best Scalloped Potatoes
Bon Appétit – Why Gruyère Is the Best Cheese for Melting
America’s Test Kitchen – Perfect Potatoes Au Gratin