Capital Grill Au Gratin Potatoes Recipe: Creamy Layers with Sharp Cheddar Bite

This restaurant-quality dish brings layers of creamy potato slices baked to golden perfection with sharp cheddar. I developed this version after years of testing to match the rich, velvety texture of Capital Grill’s signature side.

The secret is in the slow bake, allowing the cheese to melt into every layer while the top forms a crisp, golden crust. Simple ingredients, precise technique, and creamy results every time.

Ingredients for Capital Grill Au Gratin Potatoes

Thinly sliced potatoes meet sharp cheddar and Gruyère in this luxurious layered dish with a golden crust.

[recipe_ingredient_scaler]

The cheese selection is paramount for authentic Capital Grill quality. Cabot or Tillamook sharp cheddar delivers the required bite, while Gruyère (look for Emmi brand at Whole Foods) adds nutty depth. Russet potatoes are non-negotiable—their high starch content ensures creamy layers. For the dairy, Organic Valley heavy cream and whole milk provide the velvety texture this dish demands.

No Gruyère? Fontina or Swiss cheese can substitute, though the flavor profile will shift slightly. For a vegetarian Worcestershire, Annie’s makes a reliable version. The nutmeg might seem minor, but freshly grated makes a noticeable difference. If thinly slicing potatoes by hand feels tedious, a mandoline (or the slicing attachment on your food processor) ensures uniform slices that cook evenly.

Assemble this just before baking for best results. Leftovers keep in the fridge for 3-4 days and reheat beautifully. For make-ahead, prep the components separately and assemble the day of serving—this prevents the potatoes from discoloring. Freezing isn’t recommended as it can make the sauce separate.

Step-by-Step Instructions for Creamy Au Gratin Potatoes

Master this technique and you’ll achieve restaurant-quality creamy layers with a perfectly golden crust.

Step 1: Prepare the Potato Base with Aromatics

Peel and thinly slice the 2.5 lb Russet Potatoes into ⅛-inch thick rounds using a sharp knife or mandoline. Consistency in thickness ensures even cooking. Place the sliced potatoes in a large bowl of cold water to prevent browning while you work.

Finely dice the 1 whole Yellow Onion and mince the 3 cloves Garlic Cloves. In a small skillet, melt 2 tablespoons of the 0.5 cup Unsalted Butter over medium heat. Add the diced onion and cook for 5-6 minutes until translucent and tender, then stir in the minced garlic for 30 seconds until fragrant. This aromatic base infuses the dish with depth.

Step 2: Create the Creamy Cheese Sauce

In a large saucepan, melt the remaining 6 tablespoons of Unsalted Butter over medium heat. Whisk in the 0.25 cup All-Purpose Flour to form a smooth roux. Cook for 2 minutes, stirring constantly, until the mixture turns a pale golden color—this removes the raw flour taste.

Gradually whisk in the 2 cups Whole Milk and 1 cup Heavy Cream, ensuring no lumps form. Stir in the 1 tbsp Dijon Mustard, 1 tsp Worcestershire Sauce, 0.25 tsp Nutmeg, 1 tsp Kosher Salt, and 0.25 tsp Freshly Ground Black Pepper. Cook for 5-7 minutes, stirring frequently, until the sauce thickens enough to coat the back of a spoon.

Remove the sauce from heat and stir in 1 cup Gruyère Cheese and 1 cup Sharp Cheddar Cheese until fully melted and smooth. The combination of these cheeses creates a rich, complex flavor profile with a perfect melt.

Step 3: Layer and Bake to Perfection

Drain and pat dry the sliced potatoes. Grease a 9×13-inch baking dish with a small amount of butter or non-stick spray. Begin layering by spreading a thin layer of the cheese sauce on the bottom of the dish. Add a single layer of potato slices, slightly overlapping, followed by a sprinkle of the remaining 0.5 tsp Kosher Salt and 0.25 tsp Freshly Ground Black Pepper. Drizzle with a portion of the cheese sauce.

Repeat the layers, ending with a final layer of sauce. Sprinkle the remaining 1 cup Sharp Cheddar Cheese evenly over the top. Cover the dish with aluminum foil and bake in a preheated 375°F oven for 45 minutes.

Step 4: Finish with a Golden Crust

After 45 minutes, remove the foil and bake uncovered for an additional 20-25 minutes, or until the top is deep golden brown and bubbling around the edges. The potatoes should be tender when pierced with a knife, and the sauce should be thick and creamy.

Let the dish rest for 10 minutes before serving. This resting period allows the layers to set, making it easier to serve neat portions. The final result should have a creamy interior with a crisp, golden cheese crust on top.

Essential Equipment for Perfect Results

Baking Dish

A 9×13-inch glass or ceramic baking dish is essential for even heat distribution and that perfect golden crust. I prefer Pyex for its durability and heat retention. Avoid metal pans as they can cause hot spots.

Mandoline Slicer

For perfectly uniform ⅛-inch potato slices, a mandoline is a game-changer. I use the OXO Good Grips model with safety guard—it’s affordable and precise. Uniform slices ensure even cooking and professional presentation.

Heavy Saucepan

A 3-4 quart heavy-bottomed saucepan prevents scorching when making your roux and cheese sauce. I swear by All-Clad stainless steel for its even heat and responsive temperature control. 🔥

Whisk and Wooden Spoon

A sturdy stainless steel whisk is crucial for lump-free roux and sauce. Pair it with a wooden spoon for stirring the sauce as it thickens. These are my most-reached-for tools in the kitchen.

Cheese Grater

Freshly grated cheese melts better than pre-shredded. A box grater works, but I prefer the Microplane for finer shreds that incorporate seamlessly into the sauce. Always grate just before using.

Thermometer

While not traditional, a instant-read thermometer ensures your dish reaches the perfect 165°F internal temperature. I use ThermoWorks for accuracy. This prevents over or under baking.