Ingredients

The following ingredients have 8 Servings
  • ¼ cup olive oil
  • 2 medium yellow onions (halved and thinly sliced)
  • 2 tsp Kosher salt
  • 3 lb russet potatoes
  • 2 cloves garlic (minced)
  • 2 tbsp unsalted butter
  • ½ cup white wine
  • 1 pint heavy whipping cream (about 2 cups)
  • 1 tbsp finely chopped thyme leaves
  • ½ tsp white pepper
  • ½ tsp garlic powder
  • ¼ tsp cayenne pepper (optional)
  • 3/4 cup shredded gruyere cheese

Instruction

  • In a large skillet over medium heat, add the olive oil, onions and 1 tsp of salt. Stir to combine. Let the onions caramelize for 35-40 minutes, stirring often so that they brown but being careful not to burn.
  • While the onions are caramelizing, peel your potatoes and slice them into 1/4-inch rounds. I prefer to use a mandolin to ensure they are a uniform ¼ inch thickness, but if you do not have one, you can cut them carefully with a sharp knife in as even slices as you can get!
  • Add the sliced potatoes to a large bowl and fill with water until they are just covered, set aside (this helps prevent them from browning while you finish your onions).
  • Preheat your oven to 375℉ and grease a 9x13 baking dish.
  • Once the onions are caramelized, drain off any excess oil then place back over medium heat.
  • While the oven preheats, add the garlic and butter to the skillet with the onions. Melt the butter and sauté the garlic for about a minute.
  • Add the white wine to the skillet and let it cook until it has reduced by half, about 2 minutes. Once reduced, add the heavy cream and whisk to combine and bring to a simmer. Stir in the thyme, white pepper, garlic powder, cayenne (if using) and the remaining 1 tsp of salt. Stir to combine and cook, simmering and stirring often, to allow the flavors to mend and the sauce to slightly thicken, 4 more minutes. Remove from heat and set aside while you begin to layer your potatoes.
  • Drain the potatoes then add ½ of the potatoes to the bottom of the greased 9 x 13 pan in an even layer. Pour ⅓ of the sauce over the first layer of the potatoes (about 1 cup) then add ¼ cup of the cheese. Next, add the remaining potatoes then pour the remaining sauce over (do not add the remaining cheese yet!)
  • Cover with foil and transfer to the preheated oven and bake until the potatoes are just fork-tender, about 40 minutes.
  • Once tender, carefully remove the potatoes from the oven and increase your heat to 425℉.
  • Remove the foil and top the potatoes with the remaining ½ cup of cheese. Place back into the oven and cook, uncovered, for 8 to 10 minutes, or until the cheese is bubbly and lightly browned over the top.
  • Let cool for 5 to 10 minutes before serving! Enjoy!