Ingredients:

  • lbs Russet or Yukon Gold Potatoes, peeled
  • cups Heavy Cream (35% fat)
  • cup Whole Milk
  • oz Gruyère Cheese, freshly grated
  • Tbsp Prepared Sharp White Horseradish
  • Tbsp Dijon Mustard
  • cloves Garlic, finely minced
  • tsp Fresh Thyme Leaves
  • Tbsp Unsalted Butter, for greasing
  • tsp Kosher or Sea Salt, divided
  • /2 tsp Freshly Ground Black Pepper, divided

Instructions:

  1. Preheat oven to 375°F (190°C). Generously butter the 9x13 inch baking dish.
  2. Peel potatoes. Using a mandoline set to 1/8 inch (3mm) thickness, slice all potatoes. Do not rinse the sliced potatoes; the starch is needed for binding.
  3. In a saucepan over medium heat, combine heavy cream, milk, minced garlic, Dijon mustard, horseradish, thyme, 1 teaspoon of salt, and 1/2 teaspoon of pepper. Heat gently until just steaming (do not boil). Remove from heat and let steep for 10 minutes.
  4. Arrange one-third of the sliced potatoes in an overlapping pattern in the prepared dish. Sprinkle lightly with remaining salt and pepper. Pour one-third of the infused cream mixture evenly over the potatoes.
  5. Repeat the layering process twice more with the remaining potatoes, cream mixture, salt, and pepper.
  6. Sprinkle two-thirds of the grated Gruyère evenly over the top layer. Cover the dish tightly with foil and bake for 45 minutes.
  7. Remove the foil. Sprinkle the remaining Gruyère on top. Return the dish to the oven, uncovered, and bake for another 15–30 minutes, or until the top is deeply golden brown, bubbling, and a knife slides easily through the centre.
  8. Let the Dauphinoise rest on a cooling rack for 10 minutes before scooping and serving alongside your roast.