Cheesy potatoes au gratin layer thin Yukon Gold slices with a sauce made from sharp cheddar, smoked Gouda, and garlic-herb soft cheese. Onion, garlic, Herbs de Provence, and mustard powder give the rich half-and-half sauce a savory, aromatic base.
The dish bakes covered until the potato layers are nearly tender, then finishes uncovered beneath more cheddar and Gouda. Uniform slices, gradual additions of dairy, and a 10- to 15-minute rest are the details that create smooth sauce and clean portions.
Ingredients for Cheesy Potatoes Au Gratin
The sauce begins with 4 tablespoons salted butter, one diced yellow onion, 4 to 5 minced garlic cloves, and 1/4 cup all-purpose flour. Add 4 cups room-temperature half-and-half, 1 tablespoon Herbs de Provence, 1 teaspoon dry mustard, 1 teaspoon salt, and 1/2 teaspoon black pepper.
Melt 1 cup freshly shredded sharp cheddar, 1 cup freshly shredded smoked Gouda, and one 5.3-ounce garlic-and-herb soft cheese into the sauce. Layer it with 3 pounds thinly sliced Yukon Gold potatoes. Another cup each of cheddar and Gouda forms the final topping. Use butter or cooking spray for the baking dish.
If you enjoy this recipe, you may also like Creamy Tortellini Bake.
How to Make Cheesy Potatoes Au Gratin
- Prepare the dish. Heat the oven to 375°F, generously butter an 11-inch pie plate or similar dish, and place it on a sheet pan.
- Cook the aromatics. Melt 4 tablespoons butter over medium heat. Cook onion about 5 minutes, then add garlic for 1 minute.
- Make the roux. Whisk in flour and cook for 1 to 2 minutes.
- Add the dairy. Pour in room-temperature half-and-half about 1 cup at a time, whisking until the sauce is smooth and thick.
- Melt the cheeses. Stir in herbs, mustard, pepper, salt, 1 cup cheddar, 1 cup Gouda, and all the garlic-herb cheese over low heat.
- Layer the potatoes. Arrange one-third of the thin slices in the dish, salt lightly, and cover with one-third of the sauce. Repeat twice.
- Bake covered. Seal with foil and bake about 1 hour, until the potatoes are mostly tender.
- Finish uncovered. Add the remaining cheddar and Gouda and bake 20 to 30 minutes, until golden and bubbling.
- Rest. Wait 10 to 15 minutes before serving.
For storage details after serving, the USDA leftovers and food safety guidance.
Slice the Potatoes to an Even Thickness
Uniform slices cook at the same rate and settle into neat layers. A mandoline is the fastest way to create consistent thin rounds, but a sharp chef's knife also works. Use the mandoline's guard and stop before the potato becomes too small to hold safely.
Yukon Gold potatoes bring a naturally buttery flavor and hold their shape while becoming tender. Keep the slices together as you work so they can be arranged in overlapping rows without long exposure to air.
If you enjoy this recipe, you may also like Copycat Taco Bell Mexican Pizza.
Build a Stable Cream Sauce
Cook onion in butter until softened, then add garlic only for the final minute. Once flour is whisked in, the 1- to 2-minute cooking time removes its raw taste and creates the roux that keeps the dairy sauce from becoming watery.
Room-temperature half-and-half blends more readily than cold dairy. Add it in stages and whisk each portion smooth before adding the next. The sauce should thicken enough to coat the whisk before the cheese goes in.
Melt the Three Cheeses Gently
Sharp cheddar adds tang, smoked Gouda brings depth, and garlic-herb soft cheese makes the sauce creamy and aromatic. Reduce the burner to low and stir until each cheese disappears into the sauce without boiling it.
Reserve half of the cheddar and Gouda for the top. Dry mustard sharpens the cheese flavor without making the sauce taste strongly of mustard, while Herbs de Provence carries the herb profile through every layer.
Layer, Cover, and Finish Uncovered
Divide both potatoes and sauce into thirds before starting so the last layer receives enough sauce. Overlap the slices, season each potato layer lightly, and spread sauce to the edges. The foil must be tight during the first hour because trapped steam tenderizes the potatoes.
Test the center with a thin knife before removing the foil; it should meet only slight resistance. Add the reserved cheese and continue uncovered until the top is browned and the edges bubble. The sheet pan catches any overflow.
Why the Resting Time Is Essential
The sauce is fluid and extremely hot when the gratin leaves the oven. Resting for 10 to 15 minutes lets the potato starch and cheese bring it to a spoonable consistency.
Use a pie server or broad spatula to lift portions from beneath the layers. Cutting too soon causes the sauce to run across the plate and makes the overlapping slices harder to keep intact.
Troubleshooting
- Firm potato slices: Use uniform thin rounds and keep the foil sealed until the center is tender.
- Lumpy sauce: Add half-and-half gradually and whisk before each addition.
- Oily cheese sauce: Reduce the heat and avoid boiling after adding cheese.
- Pale topping: Continue uncovered until bubbling and golden.
- Runny portions: Allow the full 10- to 15-minute rest.
Serving, Storage, and Reheating
This rich gratin pairs well with roasted chicken, glazed ham, or beef and a green vegetable. Serve smaller portions when it accompanies several holiday side dishes.
Refrigerate cooled leftovers airtight for up to 4 days. Reheat a covered portion in a 325°F oven with a small splash of milk for about 25 minutes, uncovering near the end if the top needs refreshing. Individual portions can be microwaved in short intervals, though the surface will be softer.
Conclusion
Make an onion-garlic roux, gradually whisk in half-and-half, and melt cheddar, smoked Gouda, and garlic-herb cheese into the sauce. Layer it with thin Yukon Gold potatoes, bake covered at 375°F for 1 hour, then add more cheese and finish uncovered for 20 to 30 minutes.
Frequently Asked Questions
- → What potatoes are best for this gratin?
Yukon Gold potatoes provide buttery flavor, tender texture, and slices that hold their shape well.
- → Why should the half-and-half be room temperature?
Room-temperature dairy blends into the roux more smoothly and reduces the chance of a seized or uneven sauce.
- → How do I know the potatoes are tender?
After the covered bake, a thin knife inserted into the center should pass through the layers with only slight resistance.
- → How long do potatoes au gratin keep?
Refrigerate cooled leftovers in an airtight container for up to 4 days.