Potato and leek gratin has been a favorite in my family for as long as I can remember. I first started making it as a way to upgrade those boxed au gratin potatoes we all secretly love. (You know the ones—powdered cheese and all.) But something magical happened: it quickly became a family staple and the ultimate side dish. I mean, layers of tender potatoes, caramelized leeks, and creamy, cheesy goodness? It’s impossible to resist.
This post contains helpful tips and tricks! If you’re in a rush, please use the “Jump to Recipe” above!
💭 Way better than boxed potato leek gratin!
This potato and leek gratin is warm, cheesy, and incredibly satisfying. I remember making it for a potluck once, and someone actually asked me if it was a family recipe passed down for generations. It’s that good! You’ll love how easy it is to layer everything together, pop it in the oven, and let it work its magic.
- Simple ingredients, big flavors. With just potatoes, cream, and leeks, this dish turns pantry staples into a gourmet experience!
- Perfect side dish or main dish. Serve potato gratin for holidays, family gatherings, or even cozy weeknight dinners.
- Make-ahead friendly. Prepare it up to two days in advance to save time, perfect for stress-free entertaining or meal planning!
Love cheesy sides that will wow your guests? Try my Korean corn cheese, gouda mac and cheese, broccoli cheese casserole, or a healthy-ish cauliflower “mac”.
📋 Ingredients and notes
To make this potato leek gratin, you’ll need Russet potatoes, leeks, butter, milk, heavy cream, fresh garlic cloves, cheddar cheese, parmesan cheese, bay leaf, fresh thyme, kosher salt, and pepper.
Variations & Substitutions
- Potatoes. I used Russet potatoes, but you can also use Yukon gold potatoes. You can peel them or use them unpeeled.
- Vegetables. Aside from leeks, you can make this dish more filling by adding spinach and mushrooms.
- Butter. You can use plant-based butter or olive oil.
- Milk and heavy cream. You can substitute this with two cups of half-and-half. You can also use dairy-free milk, such as oat milk or almond milk, as a substitute for whole milk, and coconut cream as a substitute for heavy cream.
- Cheese. I used cheddar and parmesan. You can use other easy to melt cheeses like gruyère cheese, gouda, or even Swiss cheese. Or use plant-based cheese.
- Breadcrumbs. You can sprinkle breadcrumbs on top for a crispier topping.
📖 How to make potato leek gratin
Step 1:
Preheat your oven to 375℉ and grease your baking dish with butter, then set aside.
Step 2:
Cook the sliced leeks and minced garlic in the butter on a skillet on medium heat for 5 minutes, or until tender and golden.
Step 3:
Add about half of all of the sliced potatoes, sauteed leeks and garlic, salt, black pepper, and the cheeses to your casserole dish in layers in the order just listed. Then, repeat the process by adding another layer.
Step 4:
Pour the heavy cream and milk evenly over top making sure all parts are covered completely. Finally, add the bay leaf and fresh sprigs on top.
Step 5:
Cover with foil and bake for about 45 minutes, or until the potatoes are tender.
Step 6:
Remove the foil and bake for another 10 minutes. Then broil for 3-5 minutes on high until golden brown. Then, serve and enjoy!
Shruthi’s Top Tip
Layer the ingredients carefully without pressing them down to allow the cream mixture to seep through evenly.
- Wash leeks thoroughly to remove hidden dirt—slice them first, then soak in a bowl of cold water to loosen debris.
- Slice the potatoes as thinly as possible, ideally ⅛ inch, for even cooking and the best texture. Use a mandoline slicer for quick, uniform potato slices if you have one.
- Warm the milk and cream slightly before pouring it over the layers to ensure even cooking.
- Let the gratin rest for 5-10 minutes after baking to allow the layers to settle before serving.
- If you skip the broiling step, sprinkle a little extra cheese on top during the last 10 minutes of baking for a golden finish.
👩🏽🍳 Troubleshooting FAQs
Broiling gives it a beautiful golden crust and enhances the flavor, but you can skip this step if preferred. Just expect a softer top layer.
Slice them as thin as possible, about ⅛ inch thick. Thin slices ensure the potatoes cook evenly and absorb the cream fully.
No, leave the layers undisturbed. Pour the cream mixture evenly over the dish to allow it to soak through naturally.
🍴 How to serve potato leek au gratin
Serve potato leek au gratin as a side dish for family dinners, Thanksgiving gatherings, and other holiday parties. It’s also a delicious vegetarian main dish! I like serving it with roasted vegetable salad, seitan-based dishes like vegan turkey roast or vegan ham, and my mushroom Wellington.
🍴Storage and reheating suggestions
To make this ahead, assemble the gratin up to 2 days ahead, cover with foil or saran wrap and refrigerate. Bake it as instructed when ready to serve.
Store leftover potato and leek gratin in an airtight container in the refrigerator for 3-5 days. You can also freeze the grain for up to 3 months. Thaw overnight in the fridge before reheating.
To reheat, cover it with foil and reheat in the oven at 350°F for 15-20 minutes.
🍴 Other delicious, cheesy potato recipes:
If you like this recipe, check out my other potato recipes:
Cheesy Potatoes (Real Potatoes!)
Air Fryer Smashed Potatoes (Crispy, Garlic)
Stuffed Baked Potatoes
Cheesy Mashed Potatoes
If you tried this recipe, don’t forget to comment and rate! ⭐⭐⭐⭐⭐
Potato and Leek Gratin
Equipment
- Knife
- 9×13 baking dish
- Aluminum foil
Ingredients
- 2 tablespoons Butter unsalted
- 2 Leeks, washed well then thinly sliced white and light green parts only
- 2 Garlic Cloves, minced
- 2 pounds Russet Potatoes, thinly sliced
- ½ cup Cheddar Cheese, finely shredded
- ¼ cup Parmesan, grated
- 1 teaspoon Salt
- ¼ teaspoon Black Pepper
- 1 cup Heavy Cream
- 1 cup Whole Milk
- 1 Bay Leaf
- 2 sprigs thyme
Instructions
- Preheat your oven to 375℉ and grease your baking dish with butter, then set aside.
- Cook the sliced leeks and minced garlic in the butter on the stove for 5 or so minutes, until tender and golden
- Add about half of all of the sliced potatoes, sauteed leeks and garlic, salt, black pepper, and the cheeses to your baking dish in layers in the order just listed.
- Then add the rest of those same ingredients in the same order in layers.
- Pour the heavy cream and milk evenly over top making sure all parts are covered completely.
- Finally, add the bay leaf and fresh sprigs on top.
- Cover with foil and bake for about 45 minutes, or until the potatoes are tender.
- Remove the foil and bake for another 10 minutes
- Then broil for 3-5 minutes on high if desired, then serve.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
