Scalloped Potatoes and Gruyere with Roasted Garlic

Roast the garlic first — 50 minutes whole, wrapped in foil, until it goes completely soft and paste-like. This is the whole point. Not just flavor. The texture. Everything comes from that one step.

Why You’ll Love This Potato Gratin

Tastes like you cooked all day. Didn’t. Works as a side with literally anything — roasted chicken, grilled fish, nothing at all. Just eat it. The cheese stays on top, actually crispy. The cream underneath stays creamy. No weird mushy middle situation. Potatoes cook evenly because you slice them paper-thin. No raw centers. No overcooked edges. Make it the morning of. Bake it when you need it. Still works.

What You Need for Potato Dauphinoise

One whole head of garlic. Not cloves. The whole head. Wrap it tight in foil and roast it first — this matters way more than people think.

Heavy cream. 260 ml. The percentage matters less than you’d expect, but 38% works. Don’t use half-and-half or milk. It breaks.

Five Yukon Gold potatoes. Peeled. Not waxy potatoes, not russets. Yukons stay firm but still get tender. That’s the difference.

Gruyere cheese. 400 ml grated. Real Gruyere. The pre-shredded stuff works but tastes different — thinner, less nutty. If you’ve got time, buy the block.

Fresh thyme sprigs. Actual thyme. Dried tastes like hay next to this. Strip the leaves off before mixing.

Salt. Cracked black pepper. More than you think. Season the cream aggressively.

How to Make Potato Au Gratin

Start with the garlic. Slice off the top of the head — just the top, exposing all the cloves. Wrap it tight. Really tight. Foil should be sealed. Roast at 175°C for 50 minutes. The cloves should be soft and golden, almost melted. Once it cools enough to touch, squeeze the paste out from the bottom. It’ll come out like toothpaste. That’s correct.

Mix that garlic paste with the cream. Salt it. Pepper it. More than feels right. Add the thyme leaves — not the stems, the leaves. Stir until it’s uniform. Taste it. If it doesn’t taste strong, it’s not ready yet.

Slice the potatoes now. Paper-thin. Mandoline if you have it. Sharp knife if you don’t. The thickness has to be even — like 2mm or 3mm all the way through. Uneven slices cook unevenly. Some pieces will be raw. Some will disintegrate. Don’t do that.

How to Get Potatoes Au Gratin Crispy and Layered Right

Use a loaf pan. 23 by 13 cm. Something narrow, something deep. This matters because the cream-to-potato ratio works in a specific shape. Too wide and the cream spreads thin. Too shallow and the potatoes pile up and cook unevenly.

Layer them. Potato slices first — just lay them, they’ll overlap naturally. Spoon the garlic cream over. Not all of it. Maybe a quarter. Sprinkle Gruyere over that. Do it again. Potatoes, cream, cheese. Potatoes, cream, cheese. End with cheese on top. The top layer should be mostly cheese — it’ll brown, it’ll bubble, that’s the whole thing.

Bake uncovered at 175°C for 1 hour 30 minutes. Watch around the 45-minute mark. The edges should start bubbling. The cheese on top should be browning by the end. You want it golden, maybe even a bit dark at the edges. The potatoes underneath should be soft — fork-tender — but still holding together, not turning into paste.

Potato Gratin Tips and Common Mistakes

Don’t cover it. Foil traps steam and the top never crisps. Just let it sit there naked for the whole time.

The garlic paste has to be smooth. If there are lumps, push them through a sieve. Lumps don’t dissolve in cream. They just sit there weird.

Let it rest 15 minutes after baking. Don’t skip this. It’s not resting for flavor. It’s resting so the structure sets and you can actually cut it without it falling apart into a cream soup.

Slice it vertically, not horizontally. Horizontal slices separate. Vertical slices stay layered.

Make it ahead. Assemble it in the morning, cover it, stick it in the fridge. Bake it at dinner time. Takes the same 1 hour 30 minutes, maybe 5 minutes longer from cold.

The cheese should brown but not burn. If it’s getting too dark before the potatoes are done, lower the heat 10 degrees and give it more time. Your oven runs hot.

Scalloped Potatoes and Gruyere with Roasted Garlic

By Emma

Prep:

20 min

Cook:

1h 35min

Total:

1h 55min

Servings:

4 servings

Ingredients

• 1 head garlic
• 260 ml heavy cream 38 %
• 5 large Yukon Gold potatoes peeled
• 400 ml grated Gruyere cheese
• Fresh thyme sprigs
• Salt and cracked black pepper

Method

1. 1 Preheat oven to 175 C 347 F. Cut off top of garlic head exposing cloves. Wrap in foil tight. Roast 50 minutes until cloves soft and golden, squeeze paste from head once cool enough.
2. 2 Mix garlic paste with cream, season with salt and pepper generously. Add thyme leaves for a herbal lift.
3. 3 Slice potatoes paper-thin with a mandoline or sharp knife; aim for even thickness to cook uniformly.
4. 4 In a loaf pan about 23 x 13 cm, layer potato slices, then spoon over garlic cream, sprinkle Gruyere cheese. Repeat layers ending with cheese on top.
5. 5 Bake uncovered 1 hour 30 minutes. Surface should bubble and brown, potatoes fork-tender but still retaining shape.
6. 6 Let rest 15 minutes before slicing. Gives structure, prevents sluicing.
7. 7 Serve warm beside roasted meats or grilled veggies.

Nutritional information

Calories

450

Protein

18g

Carbs

30g

Fat

32g

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Frequently Asked Questions About Potato Gratin

Can I make potatoes au gratin without the roasted garlic? Not really. That’s not this recipe anymore. You could use garlic powder — like 2 teaspoons mixed into the cream — but it’s different. Sharp, not sweet. The roasted garlic is why this works.

How do I know when the potatoes are done? Fork goes through the layers without resistance. Not mushy. Just soft all the way. Cheese is bubbling at the edges. That’s the signal. Don’t rely on time. Every oven is different.

Can I use a different cheese? Gruyere has a specific melt. Emmental works. Swiss works. Cheddar gets grainy. Don’t use cheddar.

What if I don’t have a mandoline? Sharp knife. Takes longer. Just keep the slices consistent — that’s the only rule.

Can I add ham or other mix-ins? Technically yeah. Not happening here though. This is a side dish. Clean. Just potatoes and cream and cheese. If you want ham potatoes, that’s a different recipe.

How long does it keep? Three days in the fridge covered. Reheats fine in a 160°C oven for 15 minutes, covered. Doesn’t taste worse. Might taste better.

Why does mine come out soupy? Either the cream wasn’t seasoned enough — cream needs salt to thicken — or you covered it while baking. Steam breaks the structure. Don’t cover it.