When it comes to side dishes you truly can’t beat Potatoes au Gratin. It’s creamy and cheesy made with potatoes, onions, butter, and the most amazing decadent cheesy sauce. I mean, it’s not surprising that this is always the star of the show when it’s served up at the dinner table.
Not only is it luxurious and impressive but it’s super easy to make and made with super simple ingredients! Serve this up with your next family roast dinner or Thanksgiving meal and you won’t be disappointed!
What you need to make this recipe
Potatoes – Russet potatoes are the best potatoes to use for this because they are starchy and create the most delicious sauce. You want to slice them very thinly so you’ll need a sharp knife or Mandolin for slicing. Don’t use waxy potatoes!
Cheese – Gruyere is a classic cheese for making potatoes au gratin because it has a strong, salty, and nutty flavor. If you can’t find it Comte cheese or Fontina would be good substitutes or you could just use cheddar.
Milk – I recommend using whole milk to add richness and flavor to the sauce. Make sure it’s warm while making the sauce, it helps the sauce thicken quickly.
Flour – the flour is mixed with the butter to create a roux which then creates a thick white sauce when the milk is added. Any white all-purpose flour will do.
How to make Potatoes au Gratin
1. Peel and thinly slice the potatoes and onions.
2. Layer half of them in a baking dish.
3. Melt the butter in a saucepan and add the flour to create a roux.
4. Gradually whisk in the milk until you have a thick white sauce.
5. Add in the grated cheeses, salt, and pepper. Stir until melted then set aside.
6. Pour half of the sauce over the potatoes then add another layer of potatoes and onions and top with more sauce. Cover with foil and bake!
Pro tips for making this recipe
- I find the most common mistake in making a gratin is not baking it for long enough. Make sure you test the tenderness of the potatoes by inserting a sharp knife before turning that oven off!
- Thin slices of potato are important! You’ll need a sharp knife or a Mandolin to cut thin slices, try to cut the slices in even thickness so they cook evenly.
- If you can’t find Gruyere you could use comte, fontina, gouda, parmesan, or just more cheddar.
- Make sure to use whole milk for the best flavor, lower fat milk won’t give as much richness!
- If you want to add any herbs I find fresh thyme goes perfectly with the cheesy potatoes!
- Make sure to cover it with foil to bake first then remove it at the final stage so the top turns golden and slightly crispy!
Frequently Asked Questions
Can I prepare this in advance?
This is an excellent make-ahead dish especially if you’re making it for special occasions such as Thanksgiving or Christmas. Bake the day before, or even two days ahead, and heat up before serving. Make sure you cover well before refrigerating.
What’s the difference between scalloped potatoes and au gratin potatoes?
Potato gratin, otherwise known as “potatoes au gratin,” is made with cheese in between the layers of the potatoes. Another difference is scalloped potatoes are usually a bit thicker than they are in a gratin.
What can I serve them with?
Potatoes au gratin goes with almost anything but you can’t beat serving them up with a roast dinner with lots of gravy and veggies such as green beans or Glazed Carrots.
Can you freeze it?
This dish doesn’t freeze well. You can make it a few days ahead of time and refrigerate before baking though.
How do I reheat leftovers?
Reheating in an oven at 350F for about 10-15 minutes until warm and bubbling is the best way but you can reheat individual portions or the whole dish in the microwave as well.
If you love this recipe try these out!
If you’ve tried this potatoes au gratin recipe then don’t forget to leave a rating and let me know how you got on in the comments below, I love hearing from you!
Potatoes au Gratin
Ingredients
- 4 Russet potatoes (about 3 lbs)
- 4 tbsp butter unsalted
- 3 tbsp flour
- 1 medium white onion
- 2 cups warm milk (480ml)
- 1 teaspoon salt (6g)
- ½ teaspoon pepper (3g)
- 1/2 cup gruyere (120g)
- 1 cup cheddar cheese
Instructions
- Preheat oven to 350F. Peel the potatoes then slice very thinly.
- Thinly slice the onion. You can cut the rings in half as well
- Assemble stacks of potato slices alternating with onion then place half of them in your casserole dish, setting the rest aside.
- Melt butter in a medium pot then add the flour and whisk over medium-high heat for about two minutes.
- Drizzle in the warm milk while whisking. Cook whale whisking until slightly thickened then remove from heat and stir in the grated cheeses. Season with salt and pepper to taste then pour half over the potatoes.
- Arrange the second layer of potatoes and onion on the casserole dish and cover with the remaining sauce. Cover with foil and bake for one hour then remove foil and bake an additional 20-30 minutes or until golden brown on top and potatoes are tender.
Notes
- I find the most common mistake in making a gratin is not baking it for long enough. Make sure you test the tenderness of the potatoes by inserting a sharp knife before turning that oven off!
- Thin slices of potato are important! You'll need a sharp knife or a Mandolin to cut thin slices, try to cut the slices in even thickness so they cook evenly.
- If you can't find Gruyere you could use comte, fontina, gouda, parmesan, or just more cheddar.
- Make sure to use whole milk for the best flavor, lower fat milk won't give as much richness!
- If you want to add any herbs I find fresh thyme goes perfectly with the cheesy potatoes!
- Make sure to cover the potato gratin with foil to bake first then remove it at the final stage so the top turns golden and slightly crispy!
Nutrition
