Creamy Potato Gratin

This timeless potato gratin turns basic ingredients into a sumptuous side that works for regular dinners or fancy gatherings. Thinly cut potatoes layered with rich sauce and gooey cheese make this the ultimate comfort food.

I whipped up this gratin for friends when I wanted to make ordinary potatoes extra special. The dish was gone in minutes, and now my family asks for it at every get-together regardless of the time of year.

Ingredients

• Butter: Creates the tasty foundation for the smooth sauce that holds everything together
• Onion and garlic: Give a wonderful aroma that spreads throughout without being too strong
• Fresh thyme: Brings just the right herb flavor to balance the creaminess
• All-purpose flour: Makes the sauce thick enough to nicely coat your potatoes
• Milk or heavy cream: Forms the velvety sauce that's at the heart of any good gratin
• Gruyere cheese: Melts beautifully with a lovely nutty taste that's just right for this dish
• Nutmeg: Adds a gentle warmth that makes the dairy flavors pop
• Potatoes: Serve as the sturdy base with either russet or Yukon gold working great

Step-by-Step Instructions

Create The Base:

Heat butter on medium then toss in your chopped onion and cook till soft and clear for about 3 to 5 minutes. This slow method brings out the onions' sweetness instead of making them brown too fast.

Add Aromatics:

Toss in minced garlic and chopped thyme with the soft onions and cook just until you can smell the garlic, about a minute. Don't let the garlic brown or it'll taste bitter.

Make The Roux:

Scatter flour over your onion mix and keep stirring until everything gets coated and turns slightly golden, about a minute. This cooking gets rid of the raw flour taste while helping thicken things up.

Create The Sauce:

Slowly pour in milk or cream while constantly stirring to avoid lumps. Keep cooking and stirring until the sauce gets thick enough to stick to the back of a spoon, around one to two minutes.

Add Cheese:

Turn down the heat before adding half a cup of shredded Gruyere, gently stirring until it's fully melted. Then add nutmeg, salt and pepper to match your taste.

Layer The Potatoes:

Put a thin coat of sauce on the bottom of your dish then start layering potato slices with sauce between each layer. For a quicker approach, you can dunk each slice in sauce before placing it in the dish.

Final Assembly:

Pour whatever sauce is left over your arranged potatoes, making sure every slice gets covered, then sprinkle the rest of your Gruyere on top to create a golden crust.

Bake To Perfection:

Stick it in a 350°F preheated oven and cook until you can easily pierce the potatoes with a fork and the top turns golden and bubbly, usually taking between 45 to 60 minutes depending on your oven.

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The smell of this potato gratin cooking has become what comfort means in our house. I remember making this during a terrible winter storm when our power went out. We finished cooking it on our gas stove in a Dutch oven with the lid on and ate by candlelight. My family still talks about that night years later.

The Art Of Slicing

Getting potato slices the same thickness is super important for even cooking. A mandoline works best to get that perfect 1/8 inch thickness so everything cooks at the same speed. If you're using a knife, don't rush to keep the slices consistent. Soaking your sliced potatoes in cold water for 20 minutes before you start layering gets rid of extra starch and stops them from turning brown, but make sure to dry them completely before using.

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Perfect Cheese Selection

Gruyere might be the classic choice for potato gratin but don't be afraid to try something new. Mixing cheeses can create amazing flavors. Try sharp cheddar with smoked gouda for an American twist, or fontina with parmesan for an Italian feel. Just make sure to pick cheeses that melt smoothly rather than ones that break apart when heated.

Serving Suggestions

This fancy potato gratin goes really well with roasted meats, especially beef tenderloin or leg of lamb where the creamy potatoes balance out the rich meat. For a full meal, add a simple green salad with a tangy dressing to cut through the richness. When serving at a big dinner, let the gratin sit for 15 minutes before cutting so the pieces hold together better on the plate.

The French Connection

This dish comes from the Alpine areas of France known for amazing butter and cheese. The traditional French version called dauphinoise potatoes usually doesn't have cheese and focuses on the simple magic of potatoes and cream. Our version with Gruyere shows how the dish changed as it spread beyond France, becoming a favorite comfort food across Europe and eventually worldwide.

Frequently Asked Questions

→ Can this gratin be made in advance?

Absolutely, you can prep it a day ahead and refrigerate it covered. Before baking, let it warm for 30 minutes at room temperature. If baking straight from the fridge, give it an extra 10-15 minutes in the oven. You can also bake it fully, refrigerate, then reheat it at 350°F until warmed through.

→ What’s the best method for slicing potatoes?

Keep slices consistent and thin, about 1/8 inch (3mm) thick, so they cook evenly. A mandoline makes this easy, but if using a knife, go slow and steady with a sharp blade. Even slices are key to perfect results.

→ Which potatoes are ideal?

Both Russet and Yukon Gold potatoes work beautifully. Russets soak up the sauce and turn soft, while Yukon Golds stay firm with a buttery flavor. Combine both for the best of both worlds.

→ How do I know when the dish is done?

Look for a crisp, golden top with bubbly edges. A knife should slide through the potato layers easily when inserted. If there’s resistance, keep baking until the potatoes are totally soft.

→ What can I serve with it?

This dish pairs well with roasted meats like chicken, ham, or beef. For balance, try simple greens like roasted asparagus or a bright salad. It’s a versatile side for cozy meals or fancy spreads.

→ Can I use packaged shredded cheese?

You can, but it’s not ideal. Pre-shredded cheese often has additives that hinder melting. For smooth, flavorful results, grate fresh Gruyere or other cheeses just before using—it’ll make a big difference!