Creamy Cheesy Potatoes – Easy Au Gratin Thanksgiving Side

Cheesy au gratin potatoes are the ultimate comfort side dish — rich, creamy, golden, and bubbling with melted cheese and tender layers of thin-sliced potatoes. Whether you’re preparing a Thanksgiving feast, Christmas dinner, or a cozy Sunday roast, this dish always steals the spotlight.

This version takes the classic French-inspired gratin dauphinois and supercharges it with sharp cheddar cheese, a hint of garlic, and a velvety béchamel-style sauce. The result? A deeply savory, indulgent casserole that’s crispy on top and luxuriously creamy inside.

No Thanksgiving table is complete without these cheesy au gratin potatoes. They pair perfectly with turkey, ham, or any holiday roast — and they’ll have everyone going back for seconds.

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Ingredients Overview

Every ingredient in this dish brings richness and depth. Here’s what you’ll need:

• Russet or Yukon Gold Potatoes
  Choose starchy russets for a fluffier texture or Yukon Golds for creamier, buttery layers. Slice very thinly (about 1/8 inch) using a mandoline or sharp knife.

• Cheddar Cheese (Sharp or Extra Sharp)
  Provides the classic cheesy punch. Sharp cheddar melts beautifully and balances the creaminess with a tangy edge.

• Gruyère or Swiss Cheese (Optional)
  Adds a nutty, slightly sweet flavor — perfect for rounding out the cheddar. Optional but highly recommended.

• Heavy Cream & Whole Milk
  A mix of both creates a creamy base that isn’t overly thick. You can use all heavy cream for extra indulgence or lighten it slightly with more milk.

• Garlic
  Rubbed on the baking dish or added to the sauce for depth and aroma.

• Butter
  Used for making the roux and greasing the baking dish.

• Flour
  Helps thicken the cheese sauce. Use all-purpose flour or a gluten-free 1:1 substitute if needed.

• Salt, Black Pepper, Nutmeg
  Salt enhances flavor, pepper adds heat, and a touch of nutmeg provides classic warmth.

Ingredient Tips & Substitutions:

• Dairy-Free: Use plant-based milk, vegan butter, and dairy-free cheeses.

• Gluten-Free: Substitute flour with gluten-free all-purpose blend or cornstarch.

• Herb Add-Ins: Thyme, rosemary, or chives can be added for an herby twist.

• Cheese Swaps: White cheddar, fontina, or even pepper jack work well.

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Step-by-Step Instructions

1. Prep the Potatoes

Peel the potatoes and slice them into very thin rounds — about ⅛ inch thick. Soak slices in cold water for 10 minutes to remove excess starch (this helps with even baking and crispier edges). Drain and pat dry thoroughly with a clean towel.

2. Make the Cheese Sauce

In a medium saucepan, melt 2 tablespoons of butter over medium heat. Whisk in 2 tablespoons of flour and cook for 1–2 minutes to make a pale roux.

Slowly whisk in 1 cup whole milk and 1 cup heavy cream, stirring constantly to prevent lumps. Bring to a simmer and cook until thickened, about 4–5 minutes.

Remove from heat and stir in:

• 1½ cups shredded sharp cheddar cheese

• ½ cup shredded Gruyère (optional)

• Salt, black pepper to taste

• A pinch of ground nutmeg

Stir until smooth and velvety.

3. Assemble the Casserole

Preheat oven to 375°F (190°C). Rub the inside of a 9×13-inch baking dish with a cut clove of garlic and butter generously.

Layer half of the potatoes in the dish, overlapping slightly. Pour over half the cheese sauce. Repeat with remaining potatoes and top with the rest of the sauce.

Sprinkle with an extra ½ cup of cheddar or Gruyère on top.

4. Bake

Cover loosely with foil and bake for 45 minutes. Then uncover and bake an additional 20–25 minutes, until golden brown and bubbling.

For an extra crispy top, broil for 2–3 minutes at the end — watch carefully!

5. Rest and Serve

Let the casserole rest for 10–15 minutes before serving. This allows the sauce to thicken and the layers to settle.

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Tips, Variations & Substitutions

• Use a Mandoline: Thin, even slices cook more evenly and create that classic layered look.

• Let It Rest: Don’t skip the resting step — it helps prevent a runny casserole.

• Make Ahead: Assemble up to 1 day ahead. Cover and refrigerate, then bake before serving.

• Add Caramelized Onions or Leeks: Layer them between the potatoes for added sweetness and richness.

• Use Smoked Cheese: Smoked gouda or smoked cheddar brings a deeper, savory flavor.

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Serving Ideas & Occasions

Cheesy au gratin potatoes are ideal for:

• Thanksgiving or Christmas dinner

• Sunday roasts

• Potluck gatherings

• Hearty vegetarian side dishes

Pair with:

• Roast turkey, ham, or prime rib

• Roasted Brussels sprouts or green beans

• A crisp green salad with vinaigrette to cut the richness

Garnish with chopped chives, parsley, or crispy shallots for added flair.

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Nutritional & Health Notes

This dish is rich and indulgent — best enjoyed in balanced portions:

• Potatoes: High in potassium and fiber when skin-on (you can leave skin on Yukon Golds).

• Cheese & Cream: Provide calcium and protein, though also high in saturated fat.

Lighter Options:

• Use half-and-half instead of cream

• Reduce cheese by 25% and add a touch of Dijon mustard for flavor

• Add a layer of cauliflower or turnips to mix in lighter veggies

This dish is vegetarian and can be easily adapted for gluten-free or dairy-free diets with smart swaps.

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FAQs

Q1: Can I use pre-shredded cheese?

A1: Pre-shredded cheese often contains anti-caking agents that prevent smooth melting. For the creamiest sauce, shred your own cheese from a block.

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Q2: What’s the difference between scalloped potatoes and au gratin?

A2: Scalloped potatoes are typically baked in a simple cream or milk sauce without cheese, while au gratin potatoes include cheese — often both in the sauce and on top — and sometimes breadcrumbs.

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Q3: Can I make this ahead of time?

A3: Yes! Assemble the casserole a day in advance and refrigerate. Let it come to room temperature before baking, or add 10–15 minutes to the baking time if going straight from fridge to oven.

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Q4: How do I keep the sauce from curdling?

A4: Simmer the sauce gently and avoid overheating once the cheese is added. High heat can cause dairy to break or separate.

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Q5: Can I freeze au gratin potatoes?

A5: It’s best enjoyed fresh, but you can freeze after baking. Cool completely, then wrap tightly. Reheat covered at 350°F until warmed through. Note: texture may be slightly softer after freezing.

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Q6: What kind of potatoes are best?

A6: Russets are classic for fluffier texture; Yukon Golds offer creaminess and hold their shape better. Either works — or use a mix for the best of both worlds.

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Q7: Can I add protein to make it a full meal?

A7: Yes! Add layers of cooked bacon, ham, or sautéed mushrooms to turn it into a one-dish dinner.

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