Au Gratin Potatoes Recipe
Posted Mar 15, 2024
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This au gratin potatoes recipe is the ultimate comfort food side dish. Hearty potatoes are sliced thin, layered with onion and baked in a cheesy, homemade sauce. Learn how to make potatoes au gratin from scratch to serve at your holiday gatherings!
These are truly the best potatoes au gratin. Made completely from scratch, this recipe is comfort food at it’s finest – a must-make holiday side dish to serve to friends and family.
I mean, what’s not to love about this au gratin potatoes recipe? Starchy potatoes & sweet onions are baked in a rich, cheesy homemade sauce and topped with even more cheese.
Perfect for both adults and kids, serve potatoes au gratin alongside your favorite main dish recipes like Roast turkey, slow cooker pot roast, etc.
Au Gratin Potatoes Ingredients & Substitutions
- Yukon gold potatoes are soft and buttery. However, you can use russet or red potatoes if you prefer.
- Sweet Onion. choose your favorite variety: white or yellow.
- Salted butter. unsalted butter is a good substitute.
- Flour. make this recipe gluten-free by using an all-purpose gluten-free flour.
- Whole milk/heavy cream. This au gratin potatoes recipe calls for 2 cups of liquid dairy. You can use all whole milk, all heavy cream, or half and half if you prefer.
How to Make Au Gratin Potatoes
We’ll walk through this recipe step-by-step, and make sure you watch the video for extra guidance.
Begin by peeling and finely slicing the potatoes and onion. This can be time consuming, you can use a mandolin to speed up the process, or enlist help from family members.
Then, preheat the oven to 400°F and lightly grease a 9x13x3” baking dish with butter.
Make the Cheese Sauce
Then, make the cheese sauce by melting butter in a medium saucepan over medium heat.
Once the butter is melted, add the flour, salt garlic powder and pepper and whisk to combine. Cook for about 1 minute, or until the roux bubbles and lightly browns.
Then whisk in the milk and heavy cream.
Cook the sauce over medium heat, whisking often, until it has thickened (about 2-3 minutes). It should coat the back of a spoon or spatula.
Once thickened, stir in the cheese and whisk until melted. Then, set the sauce aside.
Assemble the Potatoes Au Gratin
You can layer the potatoes and onion before or after you make the cheese sauce. I prefer to do it after so the potatoes don’t brown.
To assemble, arrange ⅓ of the potatoes on the bottom of the prepared baking dish.
Then, top the potatoes with half of the onion slices and lightly sprinkle with salt and pepper.
Next, top the onions with the another third of the potatoes, then top that layer of potatoes with remaining onion slices and salt and pepper
Then, put the final third of the potatoes on top, and season with salt and pepper.
Next, evenly pour the cheese sauce over the top of the potatoes.
Cover the baking dish with aluminum foil and bake in the preheated oven for 1 hour and 15 minutes.
After 1 hour and 15 minutes, remove the foil and sprinkle the top with 1 cup of cheddar cheese.
Return the pan to the oven and bake, uncovered, for an additional 15 minutes. The cheese should melt and turn lightly golden brown, the filling should be bubbling, and the potatoes should be tender.
Serve
Let cool and serve slightly warm garnished with fresh herbs of your choosing if you’d like.
This au gratin potatoes recipe pairs well with many main dish recipes. Here are some suggestions:
- Serve alongside Roast Turkey on the holidays, along with our other Thanksgiving Recipes.
- They pair perfectly with slow cooker pot roast.
- Make them with the best meatloaf recipe.
Store/Freeze
Store leftovers in an airtight container in the refrigerator for up to 5 days, or in the freezer for up to 1 month. Thaw or reheat the au grain potatoes covered in a baking dish in the oven set to warm.
Au Gratin Potatoes Recipe FAQS
The biggest difference between the two dishes is that scalloped potatoes do not traditionally include cheese, while au gratin potatoes do.
A glass or ceramic, 9×13″ baking dish.
Yes, double the ingredients and bake in two, 9×13″ baking dishes.
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Potatoes Au Gratin Recipe
Ingredients
- 3 pounds Yukon gold potatoes (peeled and thinly sliced (about 5 cups))
- 1 medium onion (cut in half then thinly sliced)
- 1 Tablespoon salted butter (for greasing the pan)
Cheese sauce
- 4 Tablespoons salted butter melted
- 3 Tablespoons flour
- 1 teaspoon fine sea salt
- ½ teaspoon garlic powder
- ¼ teaspoon black pepper
- 1 cup whole milk
- 1 cup heavy cream
- 2 cups cheddar cheese shredded
Topping
- 1 cup grated sharp cheddar cheese
Instructions
- Preheat oven to 400°F. Lightly grease a 9x13x3” baking dish with butter, set aside.
Make the Cheese Sauce
- Melt butter in a medium saucepan over medium heat.
- Add flour, salt garlic powder and pepper and whisk to combine. Cook for about 1 minute, or until the roux bubbles and lightly browns.
- Whisk in milk and heavy cream.
- Cook the sauce over medium heat, whisking often, until it has thickened (about 2-3 minutes).
- Once thickened, turn off the heat, stir in the cheese and whisk until melted. Set aside.
Assemble
- Place ⅓ of the potatoes on the bottom of the prepared pan.
- Top with half of the onion slices, then lightly sprinkle with salt and pepper.
- Top onions with the another third of the potatoes, then top that layer of potatoes with the remaining onion slices and salt and pepper
- Then, put the final third of the potatoes on top, and season with salt and pepper.
- Next, pour the cheese sauce over the top of the potatoes.
Bake & Cool
- Cover the baking dish with aluminum foil and bake in the preheated oven for 1 hour and 15 minutes.
- After 1 hour and 15 minutes, remove the foil and sprinkle the top with 1 cup of cheddar cheese.
- Return the potatoes au gratin to the oven and bake, uncovered, for an additional 15 minutes. The cheese should melt and turn lightly golden brown, the filling should be bubbling, and the potatoes should be tender.
- Let cool and serve slightly warm.
Video
Notes
- Yukon gold potatoes are soft and buttery. However, you can use russet or red potatoes if you prefer.
- Sweet Onion. choose your favorite variety: white or yellow.
- Salted butter. unsalted butter is a good substitute.
- Flour. make this recipe gluten-free by using an all-purpose gluten-free flour.
- Whole milk/heavy cream. This au gratin potatoes recipe calls for 2 cups of liquid dairy. You can use all whole milk, all heavy cream, or half and half if you prefer.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
