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potatoes au gratin recipe

Potatoes au Gratin with Pancetta and Leeks

Thinly sliced potatoes layered up with sautéed leeks, crispy pancetta, gruyere and parmesan cheese topped with a delectable gorgonzola and thyme cream sauce and finished off with an extra layer of melty cheese. The perfect indulgent side dish of your dreams!
5 from 32 votes
Prep Time 20 mins
Cook Time 1 hr 15 mins
Total Time 1 hr 35 mins
Servings 12 servings
Calories 460 kcal


  • 3 lb medium/large Yukon gold potatoes
  • 8 oz gruyere cheese
  • 8 oz fresh mozzarella cheese
  • ¼ cup shredded parmesan
  • 6 oz diced pancetta
  • 2 leeks, white and light green portions
  • 2 cloves garlic, crushed I recommend fresh rather than from a jar.
  • 1 tsp fresh thyme
  • 2 cups heavy cream
  • 1 cup whole milk
  • 1 bay leaf
  • 1 sprig of fresh thyme
  • cup crumbled gorgonzola cheese
  • ½ tsp whole grain or coarsely ground mustard
  • pinch of nutmeg
  • salt & pepper


  • Prepare your ingredients.
    Peel the potatoes and use a mandoline slicer to cut ⅛th inch slices. Set aside.
    Wash the leeks by slicing them in half then running water along the insides of the layers. Then thinly slice and set aside.
    Shred the gruyere, mozzarella and parmesan cheese and mix in a large bowl. Then remove one cup of the shredded cheese (for the topping) and set aside.
    Then preheat the oven to 375 degrees F.
  • Heat a large sauce pan or Dutch oven over medium high heat and add in the diced pancetta. Cook until the fat has rendered and the pancetta is crispy, about 5 minutes.
    Use a slotted spoon to remove the cooked pancetta to a small bowl or plate and set aside. *Do not throw out the drippings.*
  • Add a swig of olive oil to the pot and then add in the leeks, crushed garlic and 1 tsp of fresh thyme leaves.
    Cook over medium for about 5 minutes until the leeks are tender. Remove from the pot to a bowl and set aside.
  • In the same pot over medium to medium high heat add in 2 cups heavy cream, 1 cup of whole milk, 1 bay leaf and a sprig of fresh thyme.
    Stirring frequently bring the mixture to just below a simmer, about 5-7 minutes.
    Then remove the bay leaf and thyme from the pot and turn the heat down to low.
    Add in ⅓rd cup of crumbled gorgonzola, a pinch of nutmeg, salt and pepper and half a tsp of mustard. Mix until well combined and remove from the heat.
    Taste and add any additional salt and pepper to your preference.
  • To assemble the gratin spray a little olive oil on the bottom of the casserole dish then shingle on the potatoes slices in a single layer. Spoon about half of the cooked leeks on top of the potatoes then sprinkle half of the cooked pancetta over the leeks. Top that with about half of the shredded cheese (be sure not to use the reserved cup).
    Repeat the layers of potatoes, leeks, pancetta and cheese and the finish with a final layer of potatoes.
    Pour them cream sauce evenly over the top of the potatoes. Then sprinkle the reserved cup of cheese evenly over the top.
  • Cover the gratin with a lid or foil and cook at 375 degrees F for 30 minutes.
    Then remove the covering, turn the heat up to 400 degrees F and cook for an additional 25 minutes.
    You can broil the gratin for 30 seconds to a minute at the end to really brown the cheese if you'd like.
  • Remove from the oven and allow to cool for at least 15 minutes before serving. Enjoy!


Serving: 1servingSodium: 348.4mgSugar: 3.6gFiber: 2.9gPotassium: 78.1mgCholesterol: 88.6mgCalories: 460kcalMonounsaturated Fat: 7.1gPolyunsaturated Fat: 0.4gSaturated Fat: 16.6gFat: 33.9gProtein: 18.4gCarbohydrates: 24.9g
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