Creamy, rich potatoes au gratin with bacon and leeks is quite the upgrade to your traditional sliced potatoes. It’s golden and bubbly with creamy potato rounds smothered in a cheesy sauce.
Why this recipe works
As if you thought au gratin potatoes couldn’t get any better… May I introduce you to potatoes au gratin with bacon and leeks. This is quite the upgrade, let me tell you.
A hefty mixture of cheese starts those thinly sliced potatoes off right, while a bit of horseradish sauce and Dijon mustard are added to the sauce for a huge boost of flavor. Top with crispy crumbled bacon and leeks cooked in the leftover fat, and you have quite the impressive side dish for anytime, anywhere.
Ingredients you will need
Get all measurements, ingredients, and instructions in the printable version at the end of this post.
Ingredient Info and Substitution Suggestions
POTATOES – We use a mandoline to slice our potatoes. This ensures our slices are of even thickness. A food processor with a slicing attachment can also be used. You can also use a sharp knife, just try to get the slices as close to the same thickness as you can.
SAUCE – You’ll use all the typical sauce ingredients here, with the addition of horseradish sauce and Dijon mustard. These two additions really pack in the flavor without being overpowering.
CHEESE – Potatoes au gratin is all about the cheese, so use a good quality block and shred it yourself. Prebagged cheese tends to make the sauce gritty. We used Gruyere and Fontina, but you can substitute with your favorite combination. Gruyere, Parmesan, sharp cheddar, and Monterey Jack cheese are all great options.
TOPPING – Cooked and crumbled bacon as well as sauteed leeks are simply a garnish, so you can omit them if desired. But they really make a difference! Leeks taste similar to sweet onion. You can substitute with either shallots or regular onion if preferred.
How to Make Potatoes Au Gratin with Bacon and Leeks
These step by step photos and instructions are here to help you visualize how to make this recipe. You can Jump to Recipe to get the printable version of this recipe, complete with measurements and instructions at the bottom.
- Preheat oven to 400 F. Spray the bottom of a 13×9 pan with cooking spray.
- Peel potatoes and slice into thin rounds, about 1/4-inch thick. Place slices into a bowl of cold water until ready to use. I’ve found it best to use a mandoline to slice the potatoes!
- In a large bowl, whisk together half and half, chicken broth, horseradish sauce, and Dijon mustard.
- Place 1/3 of the sliced potatoes into the bottom of the prepared pan.
- Pour 1/3 of the broth mixture over the potatoes.
- Sprinkle 1/3 of each of the shredded cheeses over the top.
- Repeat these layers two more times.
CHEF TIP – If you would like to season the potatoes, you can sprinkle some garlic salt and pepper onto the last potato layer.
- Bake uncovered, 1 hour, until potatoes are fork tender and top is golden brown.
- While the potatoes are baking, cook 3 slices of bacon and drain on paper towels. When cool, crumble or chop the bacon slices.
- In 1 tablespoon of the bacon grease or olive oil, sauté the leek rounds then drain on paper towels.
- Pull potatoes out with about 5 minutes of cook time left and top with bacon and leeks. Put back in the oven for the remaining time.
- Cool 10 minutes before serving. Sauce may seem a little thin, but it will thicken up as it cools!
Frequently Asked Questions & Expert Tips
Russet potatoes are your best bet for potatoes au gratin, as their starches help thicken the sauce mixture. They also absorb the creamy sauce well and cook down to be super tender, just the way we want them! Yukon Gold potatoes are another popular option, thanks to their super buttery natural flavor. Either or will work great in this recipe.
The main difference between these two dishes is simply, cheese. Scalloped potatoes are baked in a creamy sauce without cheese. While the two are similar, potatoes au gratin always contains cheese in the sauce, and often times on top.
Yes, absolutely. You can assemble the dish a day in advance and store it, covered, in the refrigerator. When ready, bake as normal. If the dish is going in cold, you may need to add an extra 10 minutes or so to the bake time.
Store cooled leftovers in an airtight container kept in the refrigerator for up to 4 days. Cover with foil and reheat in a 350F oven. Optionally add a splash of half and half or milk to keep the potatoes moist and bake for around 15 minutes or until heated through.
Serving Suggestions
Serve your potatoes au gratin with bacon and leeks with roasted chicken, beef tenderloin, or orange bourbon glazed ham for the holidays.
I love the subtle, delicious flavor of this side dish. It’s perfect for holidays and get togethers, but to be completely honest, I would make this in a smaller dish for the three of us here to go with a regular weeknight meal!
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Potatoes Au Gratin with Bacon and Leeks
IMPORTANT – There are often Frequently Asked Questions within the blog post that you may find helpful. Simply scroll back up to read them!
Print It Pin It Rate ItIngredients
- 3 pounds Russet potatoes
- 1 cup half and half
- 1 cup chicken broth
- 3 Tablespoons horseradish sauce
- 2 teaspoons Dijon mustard
- 1 cup Gruyere cheese shredded
- 1 cup Fontina cheese shredded
- 3 slices bacon
- 1 leek sliced into thin rounds
- garlic salt to taste
- black pepper to taste
Things You’ll Need
- Mandolin or sharp knife/food processor with slicing attachment
Before You Begin
- For the leeks, you will use all of the white part and a little of the green.
- We use a mandoline to slice our potatoes. This ensures our slices are of even thickness. A food processor with a slicing attachment can also be used. You can also use a sharp knife, just try to get the slices as close to the same thickness as you can.
- Use a good quality block and shred it yourself. Prebagged cheese tends to make the sauce gritty. We used Gruyere and Fontina, but you can substitute with your favorite combination. Gruyere, Parmesan, sharp cheddar, and Monterey Jack cheese are all great options.
- If you like, you can season all 3 layers of potatoes. Cheese can be salty, and because of that element, we chose to only season the top layer. You can always season to taste when they are done, but you can’t take salt back off!
Instructions
- Preheat oven to 400 F. Spray the bottom of a 13×9 pan with cooking spray.
- Peel potatoes and slice into thin rounds, about 1/4-inch thick. Place slices into a bowl of cold water until ready to use.3 pounds Russet potatoes
- In a large bowl, whisk together half and half, chicken broth, horseradish sauce, and Dijon mustard.1 cup half and half, 1 cup chicken broth, 3 Tablespoons horseradish sauce, 2 teaspoons Dijon mustard
- Place 1/3 of the sliced potatoes into the bottom of the prepared pan.
- Pour 1/3 of the broth mixture over the potatoes.
- Sprinkle 1/3 of each of the shredded cheeses over the top.
- Repeat these layers two more times.If you would like to season the potatoes, you can sprinkle some garlic salt and pepper onto the last potato layer.
- Bake uncovered, 1 hour, until potatoes are fork tender and top is golden brown.
- While the potatoes are baking, cook bacon and drain on paper towels. When cool, crumble or chop the bacon slices.3 slices bacon
- In 1 tablespoon of the bacon grease or olive oil, sauté the leek rounds then drain on paper towels.1 leek
- Pull potatoes out with about 5 minutes of cook time left and top with bacon and leeks. Put back in the oven for the remaining time.
- Cool 10 minutes before serving. Sauce may seem a little thin but it will thicken up as it cools!
Expert Tips & FAQs
- Store cooled leftovers in an airtight container kept in the refrigerator for up to 4 days. Cover with foil and reheat in a 350F oven. Optionally add a splash of half and half or milk to keep the potatoes moist and bake for around 15 minutes or until heated through.
- You can assemble the dish a day in advance and store it, covered, in the refrigerator. When ready, bake as normal. If the dish is going in cold, you may need to add an extra 10 minutes or so to the bake time.
Nutrition
The recipes on this blog are tested with a conventional gas oven and gas stovetop. It’s important to note that some ovens, especially as they age, can cook and bake inconsistently. Using an inexpensive oven thermometer can assure you that your oven is truly heating to the proper temperature. If you use a toaster oven or countertop oven, please keep in mind that they may not distribute heat the same as a conventional full sized oven and you may need to adjust your cooking/baking times. In the case of recipes made with a pressure cooker, air fryer, slow cooker, or other appliance, a link to the appliances we use is listed within each respective recipe. For baking recipes where measurements are given by weight, please note that results may not be the same if cups are used instead, and we can’t guarantee success with that method.
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Sherry says
Can you buy pre shredded cheese, or is better to buy it and shred yourself?
Amanda Davis says
For this dish, pre-shredded cheese should be ok. It can be hard to find fontina and/or gruyere shredded though. I believe that you CAN ask the deli department to shred cheese for you!
Tony says
Can I substitute garlic for the horseradish?
Amanda Formaro says
Hi, Tony. I don’t see why not. Let me know how it turns out for you! :)
Liz says
A lovely recipe. Thank you and have a great day!