Creamy Au Gratin Potatoes

These creamy Au Gratin Potatoes come out bubbling and golden with each bite layered in rich Gruyere and Parmesan, tender slices of potato, and a fragrant sauce infused with fresh thyme and garlic. This is that beloved comfort side that never fails to please a crowd and is completely make-ahead friendly so you can focus on enjoying dinner stress-free.

I remember the first time I made this recipe for my in-laws and watched everyone reach for second helpings That creamy sauce thickened just right over the potatoes is always the showstopper at our table

Ingredients

• Yellow onion: diced finely for a sweet aromatic base Use one small onion and pick one that is firm and has no blemishes
• Salted butter: gives the onions richness and depth A quality European-style butter can add extra creaminess
• Fresh garlic: to infuse the sauce with gentle sharpness Always use fresh cloves for the best flavor
• Fresh thyme leaves: add a floral woodsy note Select vibrant green sprigs with no wilt
• Heavy cream: forms the backbone of a lush velvety sauce Look for cream labeled heavy or whipping with at least 36 percent fat
• Milk: stretches the cream and balances richness Use whole milk for the best results
• Gruyere cheese: for that classic nutty meltability Hand-shred from a block for smoothest texture and taste
• Parmesan cheese: brings salty and savory complexity Grate fresh from a wedge if possible
• Salt and black pepper: bring balance and subtle bite Use freshly ground pepper for extra warmth
• Russet potatoes: slice thin for tender layers and thickening Choose large unblemished potatoes with tight skins
• Chives: for a fresh green garnish and a little bite Snip just before serving to keep them vibrant

Step-by-Step Instructions

Prepare the Baking Dish:

Lightly grease a 2.5 quart baking dish or a standard 9 by 13 inch pan to prevent sticking and make cleanup easy

Caramelize the Onions:

Dice the yellow onion and cook it slowly with salted butter over medium heat for about ten minutes until soft and translucent Lower the heat and continue to cook another ten to fifteen minutes stirring often until the onions turn golden and just begin to brown This process develops a sweet flavor base

Add Aromatics:

Stir minced fresh garlic and thyme leaves into the onions Let them cook gently for two minutes The kitchen will fill with their fragrance which tells you the flavors are blooming

Prepare and Add the Cream Sauce:

Combine heavy cream and milk in a measuring cup and warm briefly Just one minute in the microwave helps them meld Pour slowly into the onion mixture after letting the pot cool for a minute so the dairy does not curdle Gradually bring everything to a gentle boil over medium high heat then take it off the burner

Melt in the Cheese:

Hand grate the Gruyere and Parmesan cheese Begin stirring them in by handfuls letting each portion fully melt before adding more This step creates a smooth creamy sauce Stir in your salt and pepper now as well

Slice the Potatoes:

Wash and peel your russet potatoes then slice them as thin as possible about one eighth inch A mandoline slicer makes this fast and even Take care with your fingers and always use the guard

Layer and Assemble:

Arrange a third of the sliced potatoes on the bottom of your pan Sprinkle lightly with salt Pour over a third of the cheese sauce Spread everything gently to the corners Repeat this layering process two more times so all potatoes and sauce are used Layering ensures every bite is both creamy and flavorful

Bake Covered Then Uncovered:

Cover tightly with foil and bake at three hundred fifty degrees Fahrenheit for one hour Remove the cover and continue baking for thirty minutes for a golden finish Broil for just a minute or two right at the end if you want the top extra brown and bubbly Watch closely

Rest and Serve:

Let the dish rest at least five to ten minutes before serving This resting time thickens the sauce Sprinkle snipped chives over the top for a fresh finishing touch

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Gruyere is my secret weapon here and honestly the difference between good and spectacular cheese potatoes My kids always laugh because I insist on grating it myself and sneak a taste too This dish made its debut at my family’s Thanksgiving years ago and I have made it for every celebration since

Storage Tips

Cool leftovers to room temperature then refrigerate in a covered container for up to five days The sauce will stay creamy but can thicken further when chilled If frozen the potatoes might lose some of their original texture but will still taste great Thaw completely and reheat gently

Ingredient Substitutions

Fontina or a mild cheddar can swap in for Gruyere if needed though Gruyere is classic and gives such rich flavor Yukon Gold potatoes work in place of russets if you love a slightly more buttery slice but avoid red or waxy potatoes which stay too firm

Serving Suggestions

Au Gratin Potatoes are wonderful alongside roasted chicken steak or ham They also play well with lightly dressed greens or roasted broccoli For potlucks pre-portion in small ramekins for a special touch

Cultural Context

Au Gratin describes both the French method of browning a dish under broiler heat and the creamy layered casseroles that have won hearts everywhere The American twist on this classic is all about generous cheese and thick layers making it a comfort food beloved at family gatherings

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Frequently Asked Questions

→ What kind of potatoes work best?

Russet potatoes are ideal due to their high starch content, which helps thicken the sauce and absorb flavors. Yukon Golds are the next best option, while red or waxy potatoes are less suitable.

→ How thin should I slice the potatoes?

The slices should be about 1/8-inch thick. Using a mandoline ensures evenly thin slices that cook through perfectly without remaining firm inside.

→ Can I prepare this dish ahead of time?

Yes. Assemble and bake partially, cool, then refrigerate for up to two days. Finish baking before serving for best texture and flavor development.

→ Is it necessary to use Gruyere cheese?

Gruyere lends a distinct nutty flavor and smooth melt. Parmesan adds depth, but Fontina or mild Cheddar can be substituted if Gruyere isn’t available.

→ How do I achieve a golden top?

After baking uncovered, place the dish under a broiler for 1-2 minutes to get a bubbly and golden brown finish. Watch closely to prevent burning.

→ How should leftovers be stored?

Store cooled portions in an airtight container in the refrigerator for up to five days. While the dish can be frozen, texture may change slightly on reheating.