Classic Au Gratin Potatoes Recipe – Creamy Cheesy Casserole Delight

Ultra-creamy Classic Au Gratin Potatoes feature thin slices of Yukon Gold potatoes baked in a rich cheddar-Parmesan cheese sauce. This easy make-ahead holiday side serves 10-12 with tender texture and golden bubbly top.

Why You’ll Love This Recipe

Classic Au Gratin Potatoes deliver restaurant-quality comfort in a homey casserole. The foolproof roux-based sauce clings perfectly to each slice without sogginess.​

Make-ahead convenience saves holiday stress: assemble ahead or par-bake for quick reheating. Customizable with Gruyere swaps or lighter milk options while keeping that craveable cheesiness.​

Families rave about the even layering and crisp top after resting. Ready in 90 minutes mostly hands-off at 350 degrees F.

| Nutrition (per serving, 12 servings) | Amount |

• | Calories | 380 |
  | Total Fat | 15g (19% DV) |
  | Saturated Fat | 9g (45% DV) |
  | Carbs | 45g (16% DV) |
  | Protein | 12g |
  | Sodium | 420mg (18% DV) |

Values approximate; adjust for variations.​

Ingredients

For the Potatoes:

• 2.5 pounds Yukon Gold potatoes (about 8 medium), peeled and sliced 1/8-inch thick
• 1 medium yellow onion, thinly sliced
• 2 cloves garlic, minced

For the Cheese Sauce:

• 3 tablespoons unsalted butter
• 3 tablespoons all-purpose flour
• 2 cups whole milk
• 1 cup heavy cream
• 1.5 cups shredded sharp cheddar cheese
• 1/3 cup grated Parmesan cheese
• 1 teaspoon kosher salt
• 1/2 teaspoon black pepper
• 1/4 teaspoon ground nutmeg (optional for warmth)

Topping:

• 1/4 cup shredded sharp cheddar (extra)
• 2 tablespoons grated Parmesan

Yields 10-12 servings. Prep 30 mins, Cook 90 mins.

Best Potatoes for Au Gratin

Yukon Gold potatoes strike the ideal balance for Classic Au Gratin Potatoes. Their moderate starch content absorbs sauce beautifully while holding shape during baking.​

| Potato Type | Best For | Texture Notes |
| Russet | High starch holds layers | Can turn mushy if overbaked |
| Yukon Gold | Moderate starch, buttery | Gold color, tender-creamy perfect match |
| Red Potatoes | Waxy, low starch | Firmer slices, less sauce absorption |

Slice uniformly with a mandoline for safety and even cooking. No need to soak unless using Russets.​

Step-by-Step Instructions

Step 1: Prep Potatoes

Peel and slice potatoes to 1/8-inch thick using a mandoline or sharp knife. Place in cold water if not using immediately to prevent browning. Thinly slice onion.​

Step 2: Make Cheese Sauce (Roux Method)

Melt butter in large saucepan over medium heat. Add minced garlic and onion slices; saute 2 minutes until fragrant.

Stir in flour; cook 1-2 minutes to form roux (light golden, no raw flour smell). Slowly whisk in milk and heavy cream. Simmer 5-7 minutes until thickened (coats spoon back).​

Remove from heat. Stir in 1.5 cups cheddar, 1/3 cup Parmesan, salt, pepper, nutmeg until smooth. Taste; adjust seasoning.

Step 3: Assemble Casserole

Preheat oven to 350 degrees F. Grease 9×13-inch baking dish.

Layer one-third potatoes, one-third onions, one-third sauce. Repeat layers twice, ending with sauce. Gently press down; sauce should just cover top.​

Sprinkle extra 1/4 cup cheddar and 2 tablespoons Parmesan over top.

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Step 4: Bake to Perfection

Cover tightly with foil. Bake 60 minutes until potatoes tender (knife inserts easily).

Remove foil; bake 25-30 minutes more until top golden bubbly. Broil 1-2 minutes for crisp if desired. Rest 10-15 minutes before serving.

Total time: 90 minutes. Serves hot for best cheese pull.

Variations

Instant Pot Au Gratin Potatoes: Layer in pot, pour sauce, pressure high 5 minutes, natural release 10 minutes, then air fry top 375 degrees F 10 minutes.​

Garlic Parmesan Twist: Add 1 teaspoon dried thyme to roux; swap half cheddar for Gruyere.

Lighter Version: Use half-and-half instead of cream; skip nutmeg for neutral taste.

| Variation | Cook Time | Key Change |
| Instant Pot | 25 mins total | Pressure + air fry crisp |
| Air Fryer | 45 mins | 375 degrees F layers |
| Vegan | 50 mins | Coconut milk, cashew cheese |

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Expert Tips for Perfect Results

Fresh-grate cheese for smooth melt; pre-shredded contains anti-caking agents that seize sauce.​

Simmer roux low to avoid lumps or curdling. Taste sauce before layering.

Resting firms slices for clean cuts. Overbaking dries edges; tent foil if browning too fast.

Double batch freezes well: assemble, wrap foil, bake from frozen adding 20 minutes covered.​

Make-Ahead & Storage

Make-Ahead: Assemble fully (no bake), cover, fridge up to 24 hours. Add 1/4 cup extra cream before baking. Or par-bake covered 60 minutes; cool, fridge, reheat 350 degrees F covered 20-25 minutes + 10 uncovered.

Storage: Fridge airtight 4-5 days. Reheat oven 350 degrees F covered with foil splash milk.

Freeze: Assembled unbaked up to 2 months. Thaw overnight; bake per instructions +10 minutes. Excellent leftovers!​

Serving Suggestions

Classic Au Gratin Potatoes pair richly with lean proteins.

| Main Dish Pairing | Why It Works |
| Roast Beef or Prime Rib | Juicy meat cuts creamy richness |
| Baked Ham | Holiday classic balance |
| Grilled Steak or Salmon | Weeknight surf-turf upgrade |
| Roasted Chicken | Family Sunday comfort |
| Green Beans or Salad | Crisp veggie contrast |

Garnish fresh parsley. Serves 10-12 generously.​

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Common Questions

What’s the difference between au gratin and scalloped potatoes?
Au gratin features cheese sauce; scalloped uses cream without cheese thickening.​

Can I make dairy-free Au Gratin Potatoes?
Yes: full-fat coconut milk + vegan cheddar shreds or cashew-based sauce. Use olive oil roux.​

What if I only have Russet potatoes?
Fine alternative; soak slices 30 minutes in cold water to remove excess starch for better texture.​

How do I prevent a watery casserole?
Uniform thin slices, full roux simmer, no low-fat dairy, bake covered first to steam evenly.

Can I assemble ahead for holidays?
Absolutely; fridge 1 day or freeze 2 months. Par-bake option for day-of ease.

Is this recipe gluten-free?
Swap 1:1 gluten-free flour in roux. Check cheese labels.​

More FAQs? Drop in comments below.

This Classic Au Gratin Potatoes recipe creates the ultimate cheesy side everyone craves. Pin for holidays, tweak spice levels, share your results. Updated January 2026.​

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