Two-Potato Gratin with Maille Mustard

I think we can all agree that the sides are just as, if not more important than the entrée of any holiday gathering. Everyone has their favorites and looks forward to them all year. Create a new tradition with this Two-Potato Gratin with Maille Mustard.

Two-Potato Gratin with Maille Mustard

There’s something irresistible about a gratin. Beautifully crispy and golden on top with tender wafer thin potatoes hugged in a decadent and creamy sauce. This version gets an update with not only deux potatoes, but two types of mustard as well.

One Potato, Two Potato

Two-Potato Gratin with Maille Mustard combines the classic russet potato with the festive addition of sweet potatoes. Not only is this dish show stopping, but the natural sweetness of the beautifully bright sweet potatoes adds depth and dimension to each bite.

All gratins start with a luscious sauce and this one deserves center stage at your holiday gathering with the addition of Maille Dijon Mustard and Maille Old Style Mustard. The Dijon adds a bright tang that elevates the rich sauce while the whole grain mustard seeds in the Old Style Mustard offer up texture and their own layer of flavor.

Two-Potato Gratin with Maille Mustard

The first bite of this gratin offers up a true taste of France. Since 1747 Maille has set the standard for premium mustard. Starting with the raw ingredients themselves, including the finest grade of mustard seeds from the Burgundy region, Maille sets the standard for premium mustard.

I love that Le Maison Maille believes that the right condiment can define a meal. The combination of the two mustards in this gratin brings out the nutty Gruyere while adding interest and as the French say, that certain je ne sais quois… that element that you can’t quite define but that sets it apart from everything else.

For even more Maille inspiration, ideas, and an amazing food community, My Maille Community Facebook Page is one of the most successful food groups on Facebook. With over 70,000 members, this group is an incredible source for recipes, hosts giveaways and fun challenges, and promotes friendship and community. They also host livestreams with their Maille Sommelier Chef Brandon. It’s more than just a passion for mustard, it’s a love of food.

Doubling Down on Two-Potato Gratin with Maille Mustard

While this elegant dish might look like you spent hours in the kitchen, it couldn’t be easier, making it the perfect holiday side. With just a couple tips and tricks I’ll break down everything you need to know to make this a new family tradition and favorite.

Two-Potato Gratin with Maille Mustard
  • You want your potato slices wafer thin. Using a mandoline will allow you uniform slices and make it easier to achieve those thin cuts.
  • The velvety body of this sauce starts with a roux. Once your butter has melted add your flour and allow it to cook for several minutes. You’re not looking to add any color to this roux, just cook out the raw flour taste. When the combination begins to smell nutty you can move on to the next step.
  • To ensure you have the smoothest possible sauce, let your milk come to room temperature. This will prevent the roux from seizing up when you add it. When it comes to adding the milk, go slow. Pour a little and whisk a little until it’s all combined.
  • Continually whisk until the sauce has thickened. Then move on to adding your seasonings, including a little nutmeg. The nutmeg is a classic addition to any béchamel sauce.
  • Arrange your potatoes however you like and then pour the luxurious sauce over the top. Finish with more freshly grated Gruyere cheese. This bakes for one hour, or until the top is golden brown.

Do you love mustard as much as I do? Make sure you check out my recipe for Maille Croque Monsieur.

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Two-Potato Gratin with Maille Mustard

Russet potatoes and sweet potatoes are combined with a decadent béchamel sauce infused with Dijon mustard and whole grain mustard.
Prep Time 10 minutes
Cook Time 1 hour 15 minutes
Course Side Dish
Servings 6


  • mandoline
  • medium skillet
  • baking dish


  • 2 sweet potatoes
  • 2 russet potatoes
  • 1/2 stick of butter
  • 2 tbsp flour
  • 2 cups milk, room temperature
  • 1 tsp Maille Original Dijon
  • 1 tsp Maille Old World Style Mustard
  • 1 cup Gruyere cheese, grated, plus extra for topping
  • 1 tsp fresh thyme, chopped
  • 1 tsp fresh rosemary, chopped
  • 1 tbsp salt
  • 1 tsp freshly cracked black pepper
  • pinch of nutmeg


  • Preheat oven at 350F degrees.
  • Peel the potatoes and slice them thin. A mandoline will give you uniform slices.
  • Heat a medium sized skillet over medium and melt your butter.
  • Sprinkle in your flour, stirring constantly to combine. Allow to cook for several minutes until it begins to smell nutty.
  • Slowly add in your milk, constantly stirring. Continue to stir until the sauce thickens.
  • Add both mustards to the sauce, stirring to combine.
  • Add your seasonings, fresh herbs, and Gruyere cheese.
  • Butter a baking dish and arrange your potato slices. Pour the sauce over the top.
  • Top with more Gruyere cheese.
  • Bake for 45 minutes covered with aluminum foil.
  • Uncover and bake for another 15-20 minutes or until the top is golden brown and bubbly.
  • Enjoy!


I used both Maille Dijon Mustard and Maille Old World Style Mustard in this recipe. 
Tried this recipe?Mention @uncomplicatedchef or tag #uncomplicatedchef!

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