I piled three different cheeses into my Cheesy Potato Au Gratin and tucked in a surprising little trick that finally clinched the cheesiest result.

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I always thought a true showstopper side had to be complicated until I made this Cheesy Potato Au Gratin that actually makes people talk. Thin slices of russet potatoes soak up molten cheese, and when I fold in Gruyere it gets that browned, slightly crisp top you’re gonna fight over.

It’s loud not subtle, the kind of dish that steals the spotlight at dinner, especially when you’re picking Recipes For Thanksgiving Dinner Sides and want something everyone remembers. I’m saying this with no shame, but you might hide the leftovers because they’ll disappear fast, and yeah you’ll thank me later.

Ingredients

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Starchy russets give body and texture mostly carbs with some fiber
Rich fat and creaminess, high calories, makes sauce silky and cling
Sharp cheddar brings salty, tangy protein, melts into gooey bold cheese
Gruyere is nutty and slightly sweet, melts smooth for depth and stretchy texture
Parmesan gives aged, salty umami boost, grated for a crisp savory finish
Onion adds sweet savory backbone when cooked, subtle natural sugars
Garlic gives a pungent warming note that brightens the rich sauce
Thyme adds earthy floral notes, lifts the dish without overpowering

Ingredient Quantities

3 pounds russet potatoes, peeled and thinly sliced (about 6 medium)

3 tablespoons unsalted butter, divided

2 tablespoons all purpose flour

2 cups heavy cream

1 cup whole milk

1 small yellow onion, finely chopped

3 cloves garlic, minced

1 teaspoon Dijon mustard

1 1/2 teaspoons kosher salt

1/2 teaspoon freshly ground black pepper

Pinch ground nutmeg (about 1/8 teaspoon)

1 1/2 cups shredded sharp cheddar cheese (about 6 ounces)

1 1/2 cups shredded Gruyere cheese (about 6 ounces)

3/4 cup freshly grated Parmesan cheese (about 2 ounces)

1 tablespoon fresh thyme leaves, chopped (or 1 teaspoon dried thyme)

1/2 cup panko breadcrumbs, optional

Fresh parsley for garnish, optional

How to Make this

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1. Preheat oven to 375°F and butter a 9×13 baking dish with 1 tablespoon of the butter. Peel and thinly slice the potatoes about 1/8 inch thick (mandoline if you got one). Rinse the slices and soak for 10 minutes if you want less starch, then pat dry.

2. In a medium saucepan melt the other 2 tablespoons butter over medium heat, add the chopped onion and cook until soft about 4-5 minutes, add the garlic and cook 30-60 seconds more.

3. Sprinkle in the 2 tablespoons flour, stir and cook 1-2 minutes to get a light roux, then slowly whisk in 2 cups heavy cream and 1 cup whole milk until smooth.

4. Add 1 teaspoon Dijon mustard, 1 1/2 teaspoons kosher salt, 1/2 teaspoon black pepper, a pinch of nutmeg and 1 tablespoon chopped thyme, bring to a gentle simmer and cook until the sauce thickens slightly about 3-5 minutes.

5. Remove the pan from heat and stir in 1 cup shredded Gruyere, 1 cup shredded sharp cheddar and 1/2 cup grated Parmesan until melted and smooth. Reserve the remaining cheeses for the top (that leaves 1/2 cup Gruyere, 1/2 cup cheddar and 1/4 cup Parmesan).

6. Layer a single overlapping layer of potato slices in the buttered dish, pour about a third of the cheese sauce over, then repeat layers until all potatoes are used and pour any remaining sauce over the top. Lightly season between layers with a little pepper and thyme if you want.

7. Evenly sprinkle the reserved cheeses over the top. If using panko mix the 1/2 cup panko with the last tablespoon melted butter and a bit of the reserved Parmesan, then sprinkle that over the cheese for a crunchy topping.

8. Cover tightly with foil and bake at 375°F for 45 minutes, then remove the foil and bake another 20-25 minutes until potatoes are tender when pierced and the top is bubbling and golden.

9. If it needs more color, broil 1-3 minutes watching very closely so it doesn’t burn. Let the dish rest 10-15 minutes so the sauce sets, then garnish with chopped fresh parsley and a few thyme leaves before serving.

Equipment Needed

1. 9 by 13 inch baking dish, buttered a bit
2. Mandoline or a sharp chef knife for 1/8 inch slices
3. Cutting board
4. Medium saucepan
5. Whisk
6. Wooden spoon or heatproof spatula
7. Measuring cups and measuring spoons
8. Box grater or microplane for the cheeses
9. Aluminum foil to cover while baking
10. Oven mitts or potholders, plus a timer you wont forget

FAQ

Q: Do I need to parboil the potatoes before baking? A: No, if you slice them thinly about 1/8 inch they’ll cook through fine in the oven, but if your slices are thicker you should parboil for 5 to 8 minutes or expect a longer bake time.

Q: Can I make this ahead of time? A: Yes, assemble the dish, cover and refrigerate up to 24 hours, then bake straight from the fridge adding 10 to 15 minutes to the cooking time; leftovers keep 3 to 4 days in the fridge and reheat covered, then uncover and broil a minute or two to crisp the top.

Q: What type of potato works best? A: Russets are ideal for a creamy, tender texture because they’re starchy, Yukon Golds work too if you want a firmer bite, avoid very waxy reds for this recipe.

Q: How do I get a golden, crunchy top? A: Mix the panko with a tablespoon melted butter and a little Parmesan, sprinkle on near the end of baking and broil 2 to 4 minutes until golden, watch it closely cause it browns fast.

Q: Can I swap or cut back on the heavy cream? A: You can use half and half or more whole milk to lighten it, but the sauce wont be as rich; keep the flour or a small cornstarch slurry to make sure it still thickens.

Q: How do I know when the gratin is done? A: The sauce should be bubbling at the edges and a knife should slide through the potato slices easily, usually about 60 to 75 minutes at 350 degrees F depending on slice thickness.

Creamy & Cheesy Au Gratin Potatoes Recipe Substitutions and Variations

Heavy cream: use 1 1/2 cups whole milk + 1/2 cup melted butter to replace 2 cups heavy cream, or just use half and half if you want it lighter — still creamy but not as rich.
Russet potatoes: swap for Yukon Golds or red potatoes; they’ll be a bit waxier and hold their shape better, so slice a little thinner so they cook through.
Gruyere: substitute Emmental, Jarlsberg or Comté for similar melt and nutty flavor, maybe a touch milder though.
Panko breadcrumbs: use plain breadcrumbs or crushed buttery crackers (Ritz), or skip them and sprinkle extra Parmesan for a crunchy, cheesy top.

Pro Tips

– Slice consistency matters. If your potato slices are all different thicknesses some will be mush and some will be crunchy, so use a mandoline with the guard or a very sharp knife and try to keep them about the same thickness. Wear a cut resistant glove if you got one, and pat slices very dry after rinsing so the sauce isn’t watered down.

– Treat the cheese and sauce gently. Remove the cream sauce from the heat before you stir in the cheese and add it in batches so it melts smoothly; grated store cheese often has anti caking stuff that makes it clump, so shred your own for the creamiest melt. Taste for salt last since the cheeses are already salty.

– Do a make ahead. You can assemble the casserole a day ahead, cover and chill, then bake straight from the fridge adding a few extra minutes to the covered bake time. Let it rest 10 to 15 minutes after baking so the sauce firms up, otherwise it’ll run when you cut it.

– For a crunchy top, mix panko with melted butter and a little grated Parmesan and sprinkle it on just before baking uncovered. If you want more color, broil for only 1 to 2 minutes and watch it the whole time, it can go from perfect to burnt fast.

Creamy & Cheesy Au Gratin Potatoes Recipe

Recipe by Bob Jones

0.0 from 0 votes

I piled three different cheeses into my Cheesy Potato Au Gratin and tucked in a surprising little trick that finally clinched the cheesiest result.

Servings

servings

Calories

751

kcal

Equipment: 1. 9 by 13 inch baking dish, buttered a bit
2. Mandoline or a sharp chef knife for 1/8 inch slices
3. Cutting board
4. Medium saucepan
5. Whisk
6. Wooden spoon or heatproof spatula
7. Measuring cups and measuring spoons
8. Box grater or microplane for the cheeses
9. Aluminum foil to cover while baking
10. Oven mitts or potholders, plus a timer you wont forget

Ingredients

3 pounds russet potatoes, peeled and thinly sliced (about 6 medium)
3 tablespoons unsalted butter, divided
2 tablespoons all purpose flour
2 cups heavy cream
1 cup whole milk
1 small yellow onion, finely chopped
3 cloves garlic, minced
1 teaspoon Dijon mustard
1 1/2 teaspoons kosher salt
1/2 teaspoon freshly ground black pepper
Pinch ground nutmeg (about 1/8 teaspoon)
1 1/2 cups shredded sharp cheddar cheese (about 6 ounces)
1 1/2 cups shredded Gruyere cheese (about 6 ounces)
3/4 cup freshly grated Parmesan cheese (about 2 ounces)
1 tablespoon fresh thyme leaves, chopped (or 1 teaspoon dried thyme)
1/2 cup panko breadcrumbs, optional
Fresh parsley for garnish, optional

Directions

Preheat oven to 375°F and butter a 9×13 baking dish with 1 tablespoon of the butter. Peel and thinly slice the potatoes about 1/8 inch thick (mandoline if you got one). Rinse the slices and soak for 10 minutes if you want less starch, then pat dry.
In a medium saucepan melt the other 2 tablespoons butter over medium heat, add the chopped onion and cook until soft about 4-5 minutes, add the garlic and cook 30-60 seconds more.
Sprinkle in the 2 tablespoons flour, stir and cook 1-2 minutes to get a light roux, then slowly whisk in 2 cups heavy cream and 1 cup whole milk until smooth.
Add 1 teaspoon Dijon mustard, 1 1/2 teaspoons kosher salt, 1/2 teaspoon black pepper, a pinch of nutmeg and 1 tablespoon chopped thyme, bring to a gentle simmer and cook until the sauce thickens slightly about 3-5 minutes.
Remove the pan from heat and stir in 1 cup shredded Gruyere, 1 cup shredded sharp cheddar and 1/2 cup grated Parmesan until melted and smooth. Reserve the remaining cheeses for the top (that leaves 1/2 cup Gruyere, 1/2 cup cheddar and 1/4 cup Parmesan).
Layer a single overlapping layer of potato slices in the buttered dish, pour about a third of the cheese sauce over, then repeat layers until all potatoes are used and pour any remaining sauce over the top. Lightly season between layers with a little pepper and thyme if you want.
Evenly sprinkle the reserved cheeses over the top. If using panko mix the 1/2 cup panko with the last tablespoon melted butter and a bit of the reserved Parmesan, then sprinkle that over the cheese for a crunchy topping.
Cover tightly with foil and bake at 375°F for 45 minutes, then remove the foil and bake another 20-25 minutes until potatoes are tender when pierced and the top is bubbling and golden.
If it needs more color, broil 1-3 minutes watching very closely so it doesn't burn. Let the dish rest 10-15 minutes so the sauce sets, then garnish with chopped fresh parsley and a few thyme leaves before serving.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.