Delicious just doesn't quite capture how good these Potatoes au Gratin with Pancetta and Leeks actually are!
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!

This Potatoes au Gratin recipe might just be my favorite holiday side dish of all time. It is absolutely luscious, packed with four kinds of cheese and a truly delectable cream sauce. The addition of sautéed leeks and pancetta takes the flavor to a new level and is well worth the effort.
This recipe is the perfect holiday side dish and pairs beautifully with roasted meat. Plus, it is easily made in advance and then simply reheated before serving.
Add this to your holiday menu and I promise your guests will be begging for more. Enjoy!
Jump to:
More side dish recipes you will love.

Equipment
- Mandoline slicer: I highly recommend using a mandoline to slice the potatoes in this recipe. Not only will it get the job done quicker but it also ensures a consistent thickness that allows the potatoes to cook evenly in the given time. This Oxo Good Grips Mandaline Slicer is one of my favorites. However, if you do decide to cut them by hand aim for a ⅛th inch thickness.
- Large casserole dish or braiser: I love using this round Le Creuset Signature Braiser, but you can use your favorite large casserole dish of any shape.
- Large sauce pan or Dutch oven: I use my Le Creuset Dutch Oven to make the cream sauce but your favorite pot or even a very deep skillet will work.
- Cutting board and knives
- Measuring cups and spoons

More recipes you will enjoy.
Classic British Roast Potatoes
Made this Potatoes au Gratin with Pancetta and Leeks recipe? Let me know what you think in the comments!
Recipe

Potatoes au Gratin with Pancetta and Leeks
Ingredients
- 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
- ⅓ cup crumbled gorgonzola cheese
- ½ tsp whole grain or coarsely ground mustard
- pinch of nutmeg
- salt & pepper
Instructions
- 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!
I love Potatoes au Gratin! The four different cheeses used in this recipe go so well together. Can't wait to share!
This dish is definitely going to be my favorite. Looks so cheesy and creamy and super delicious.
Omg this gratin was so decadent and satisfying!! The perfect side dish for our dinner tonight!
I love potatoes and this potato gratin recipe might be my favourite side dish!
As a lover of everything potato, I want this on my plate tonight! It looks so satisfying and heart-warming especially with the snow and cold!