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Potatoes au gratin is the perfect way to elevate your holiday table or weeknight dinner with a dish that looks impressive but is surprisingly easy to prepare. This recipe infuses thinly sliced Yukon Gold potatoes with garlic and fresh thyme, layered generously with melty Gruyère and sharp Parmesan for a rich, creamy side that always receives compliments.
I made this for the first time during a holiday gathering and was amazed at how a humble potato could transform into such a star dish. Now it is a staple every winter in our home.
Ingredients
- Yukon Gold potatoes: offer a creamy texture and natural buttery flavor making the gratin rich and satisfying
- Heavy cream and whole milk: blend perfectly to create a luscious sauce that is not too heavy
- Shallot: adds subtle sweetness to balance the garlic’s pungency
- Fresh thyme: provides a fragrant herbal note that brightens the dish
- Kosher salt: is essential to bring out all the flavors especially with such simple ingredients
- Gruyère cheese: melts to a perfectly gooey and nutty layer that defines this gratin over scalloped potatoes
- Parmesan cheese: adds a distinct sharpness and crispy top when baked, use fresh for best results
- Unsalted butter: for greasing the baking dish ensures nothing sticks and adds a touch of richness
Step-by-Step Instructions
- Simmer the Aromatics:
- In a medium pot, combine quartered shallot, crushed garlic, and whole thyme sprigs with half the cream and milk. Heat over medium-high, stirring occasionally, until simmering. Remove from heat, cover, and let steep for 30 minutes to infuse the cream with flavor.
- Prepare the Potatoes and Oven:
- While the cream mixture infuses, preheat the oven to 350 degrees Fahrenheit and place a rack in the center. Butter a 13 by 9 inch baking dish well. Peel the Yukon Gold potatoes and slice them into very thin 1/8 inch rounds using a mandoline or sharp knife. Keep the slices uncovered at room temperature.
- Cook the Potatoes Slightly:
- Strain the infused cream and milk through a fine-mesh sieve into a bowl to remove solids. Return the cream to the pot, add salt, and then stir in potatoes. Bring to a simmer over medium-high heat and cook for four to five minutes, stirring often, just until potatoes start to become tender and the sauce thickens. This draws out starch that helps the sauce cling to the potatoes.
- Assemble the Gratin:
- Pour one third of the potato and cream mixture into the buttered baking dish. Sprinkle one third each of shredded Gruyère, Parmesan, and fresh thyme leaves evenly over the top. Repeat this layering once more. Finish by adding the remaining potatoes and cream, Gruyère, and Parmesan. Save the last bit of thyme for garnish after baking.
- Bake and Serve:
- Place the gratin in the oven uncovered and bake for forty to fifty minutes until the top is bubbling and golden brown. Let sit for five minutes to set before sprinkling the reserved thyme over and serving.
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My favorite ingredient has to be the Gruyère. Its nutty, slightly funky flavor is what turns this from a basic potato bake into something truly gourmet. One of my best memories of this dish was sharing it around the holiday table while everyone raved about its comforting richness and perfect balance of garlic and herbs.
Storage Tips
Cool leftovers completely before covering tightly with foil or plastic wrap and refrigerate up to three days. Reheat in a 350 degree oven covered to restore creaminess without drying out. Portions reheat fine in the microwave if you are in a hurry.
Ingredient Substitutions
If Gruyère is unavailable, Emmental or a mild Swiss cheese work well although the flavor will be less complex. Half-and-half can replace the cream and milk mix for a lighter sauce. If fresh thyme is not an option, dried works but reduce quantity and add it between layers rather than steeping to avoid bitterness.
Serving Suggestions
Try serving potatoes au gratin alongside roasted meats like chicken or beef for a classic combo. It pairs nicely with a crisp green salad or steamed vegetables to balance the rich richness of the gratin.
Cultural Context
Potatoes au gratin is a French classic traditionally prepared with creamy layers of potatoes and cheese baked until golden. Unlike scalloped potatoes which typically rely on a white sauce without cheese, gratin emphasizes the golden crust of melted cheese that gives the dish its signature textural contrast.
Pro Tips
- Use a mandoline with the safety guard to get even slices that cook uniformly and look professional
- Don’t skimp on the salt – it helps the potatoes soak up the cream and emphasizes the cheese flavor
- For prettiest presentation, save the most attractive potato slices to layer on top before baking
Common Recipe Questions
- → What type of potatoes work best for au gratin?
Yukon Golds are ideal as they offer a creamy texture with medium starch, which thickens the sauce beautifully without the dryness of russets.
- → How do the cheeses contribute to the dish?
Gruyère brings a rich, nutty flavor while Parmesan adds a subtle salty sharpness, together creating a complex and balanced cheesy profile.
- → Why is the cream mixture infused with shallots, garlic, and thyme?
Simmering these aromatics in cream and milk imparts delicate savory notes that enhance the potatoes without overpowering the dish.
- → What’s the benefit of pre-cooking the potatoes in cream?
Simmering softens the potatoes slightly and activates their starch for natural sauce thickening, ensuring a creamy yet stable texture after baking.
- → Can this dish be prepared in advance?
Yes, it can be fully cooked, cooled, refrigerated for up to three days, and then reheated gently to preserve its texture and flavors.
- → How important is slicing thickness for potatoes?
Uniform, thin slices (about 1/8 inch) ensure even cooking and a delicate layering effect; a mandoline slicer is helpful to achieve this.