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This Potato au Gratin recipe is easy to make, creamy, and full of flavor. It makes for a cheesy holiday potato side dish recipe that will be the perfect addition to the dinner table.
Make this homemade au gratin potatoes all year round, a potato side dish that pairs so well with all your main courses especially all your sautéed and grilled protein of choice. Often times referred to as scalloped potatoes, the flavor of this au gratin is top-notch with the addition of whole-grain mustard. It gives it that extra boost in the flavor department. The potatoes are prepared in a creamy cheesy sauce and baked to perfection. This cheesy au gratin recipe will be your go-to holiday potato side dish recipe every year and you would want to make it all year round.
Why you will love this potato side dish recipe
- Delicious and comforting: The flavor of this potato au gratin is so good, there won’t be any leftovers.
- Easy to make: You can partially prepare some of the steps ahead and store in the fridge to bake the next day. The steps and simple and easy to follow.
- Healthy: Made with clean and healthy ingredients. Don’t like gruyere? you may substitute for light cheddar.
Ingredients you will need to make this au gratin
potatoes
Kosher salt and freshly ground black pepper
olive oil
medium yellow onion
garlic cloves
whole grain mustard
gluten free flour or cornstarch
almond milk
freshly grated nutmeg
Gruyère cheese
Fresh thyme
How to make this au gratin potatoes
- First, preheat the oven to 400F and spray a baking dish with cooking oil spray or olive oil.
- Then, add sliced potatoes and season with salt and pepper. Drizzle 2 tbsp oil and toss well to coat. Place in the preheated oven and bake for 15 minutes, or until potatoes begin to soften and the sauce is ready.
- Meanwhile, heat a rimmed pan over medium heat and drizzle with 1 tbsp oil. Sauté the onion and garlic for 2-3 minutes, or until it softens.
- Stir in the mustard and flour. Slowly pour the milk and whisk until sauce is thickened and smooth, 2-3 minutes. Season with salt, pepper, and nutmeg.
- Remove the potatoes from the oven and pour over the sauce, stirring gently to mostly cover and coat.
- Top with shredded cheese. (You can now cool and refrigerate the dish for make-ahead.)
- Return to the oven and bake for 60 minutes, or until potatoes are super tender, bubbly, and golden-brown on top. (Cooking time may vary depending on the size of the thickness of your potato slices and your oven.)
- Garnish with fresh thyme before serving.
Tips and substitutes
Milk: we used almond milk, but you may use any other milk of choice.
Mustard: whole grain mustard was used but you may use dijon mustard
Cheese: If you don’t like gruyere or want to use another cheese, consider using a mix of sharp cheddar and parmesan, or gouda.
Potatoes: consider using Yukon gold potatoes
Flour: Any flour would work for this recipe. Feel free to use cornstarch too. We love to use Whole wheat as well.
Bake time: Don’t rush them, they need a good one hour in the oven depending on your oven
FAQ’s
Technically, you don’t have to peel the potatoes. You can scrub them very clean and slice them with the peel. But, we prefer peeling the potatoes for the au gratin as you can see in our recipe. It all comes down to a personal preference.
Yes. You can fully cook the au gratin, store, and reheat later as a make ahead option to save time. We recommend not adding all the cheese so you may add the rest when its time to reheat in the oven. Also, consider cooking it half way like we noted in our recipe to save time the day of.
Yes. You may clean and slice your potatoes the day before. Once you have the sliced potatoes, place in a container filled with cold water and tightly close it. Place in the fridge until you are ready for them.
Place leftover potatoes au gratin in a tightly sealed container and store in the fridge for 3-4 days. You may freeze for up to 2 months,
What goes well with au gratin potatoes
Here are some ideas of what you can have with au gratin potatoes.
- Oven Roasted Whole Chicken
- Beef Tenderloin Roast
- Honey Mustard Chicken
- Homemade Meat Loaf
- Lemon Garlic Chicken
- Balsamic Chicken Breast
Other side dish recipes to check out
- Middle Eastern Red Lentil Soup
- Honey Glazed Roasted Carrots
- Baked Brie Recipe
- Honey Mustard Potato Salad
- Maple Roasted Butternut Squash
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Easy Potatoes Au Gratin
Ingredients
- 2 lb potatoes, peeled and thinly sliced
- Kosher salt and freshly ground black pepper, to taste
- 3 tbsp olive oil, divided
- 1 medium yellow onion, thinly sliced
- 3 garlic cloves, minced
- 1 tbsp wholegrain mustard
- 3 tbsp gluten-free flour , or cornstarch
- 2 1/2 cups almond milk
- 1 tsp freshly grated nutmeg, or to your taste
- ¾ cup grated Gruyère cheese
- Fresh thyme to garnish
Instructions
- Preheat the oven to 350F and spray a baking dish with cooking oil spray or olive oil.
- Add sliced potatoes and season with salt and pepper. Drizzle 2 tbsp oil and toss well to coat. Place in the preheated oven and bake for 15 minutes, or until potatoes begin to soften and the sauce is ready.
- Meanwhile, heat a rimmed pan over medium heat and drizzle with 1 tbsp oil. Sauté the onion and garlic for 2-3 minutes, or until it softens.
- Stir in the mustard and flour. Slowly pour the milk and whisk until sauce is thickened and smooth, 2-3 minutes.
- Season with salt, pepper, and nutmeg.
- Remove the potatoes from the oven and pour over the sauce, stirring gently to mostly cover and coat.
- Top with shredded cheese. (You can now cool and refrigerate the dish for make-ahead.)
- Return to the oven and bake for 60 minutes, or until potatoes are super tender, bubbly, and golden-brown on top. (Cooking time may vary depending on the size of the thickness of your potato slices.)
- Garnish with fresh thyme before serving.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Potatoes burned after 45 minutes at 400 degrees. Turned into an oily mess, next time I’ll try baking at 350 degrees and see how it turns out.