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Two-Potato Gratin with Maille Mustard

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 mins
Cook Time 1 hr 15 mins
Course Side Dish
Servings 6


  • mandoline
  • medium skillet
  • baking dish


  • 2 sweet potatoes
  • 2 russet potatoes
  • ½ 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. 
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