Leek and Onion Scalloped Potatoes Recipe

Give it up, my sweet friend! You cannot resist the creamy, dreamy, soul-soothing magic of Leek and Onion Scalloped Potatoes. I’m telling you, this is not just a side dish. This is a main character energy situation on a plate. If you’re looking for another hearty, one-pan wonder, you must try this Garlic Butter Steak and Potatoes Skillet.

Imagine layers of tender potato, sweet leeks, and mellow onions all swimming in the most luxurious, cheesy, garlicky cream sauce. Then it gets baked until the top is golden and bubbling. Come to Mama! This is the elegant, cozy, show-stopping side you need in your life, especially right now.

It’s perfect for a fancy Sunday supper or your next holiday table. But honestly? I’ve been known to make it just for myself on a random Tuesday. No judgment here! Let’s get into it.

Recipe Overview

Cuisine: American
Category: Side Dish
Prep Time: 25 minutes
Cook Time: 1 hour 15 minutes
Total Time: 1 hour 40 minutes
Servings: 6-8 people

Do You Love This Recipe Too?

I have a full-blown obsession. It started at a friend’s spring potluck years ago. I took one bite and my eyes literally went wide. I had to have the recipe!

I begged her for it, then I made it three times that month. The way the mild onion flavor from the leeks mingles with the rich cream? It’s pure comfort. It feels fancy but it’s so down-to-earth. That’s my kind of food.

My Shopping List for This Recipe

This dish is all about simple, beautiful ingredients coming together. Fresh leeks are the star, so grab a couple of good-looking ones! Here’s everything you’ll need.

Let’s Get Your Ingredients Ready

Get your cutting board and your favorite knife. Prepping everything first makes the assembly so easy and fun. Let’s do this!

3 tablespoons unsalted butter
2 large leeks (white and light green parts only), thinly sliced and rinsed well
1 medium yellow onion, thinly sliced
4 cloves garlic, minced
1/4 cup all-purpose flour
2 cups whole milk
1 cup heavy cream
1 teaspoon kosher salt, plus more for seasoning
1/2 teaspoon black pepper
1/2 teaspoon freshly grated nutmeg (trust me on this!)
3 lbs Yukon Gold potatoes, peeled and thinly sliced (about 1/8-inch thick)
2 cups shredded Gruyère cheese, divided
1/2 cup grated Parmesan cheese
Fresh thyme leaves, for garnish

Bringing This Recipe to Life (Step-by-Step)

Okay, friends! This is where the magic happens. Follow these steps and you’ll have a masterpiece. I believe in you!

Preheat your oven to 375°F (190°C). Butter a 9×13 inch baking dish. Get that oven hot and ready!
Melt the butter in a large skillet or Dutch oven over medium heat. Add the cleaned leeks and onion. Cook them, stirring often, until they are super soft and sweet, about 10-12 minutes. Don’t let them brown!
Add the minced garlic and cook for just one more minute until it’s fragrant. Your kitchen should smell amazing right now.
Sprinkle the flour over the leek mixture. Stir constantly for about 2 minutes. This cooks the flour taste out and makes your sauce thick and perfect.
Slowly pour in the milk and cream, whisking the whole time to avoid lumps. Bring it to a gentle simmer. The sauce will start to thicken beautifully.
Take the pot off the heat. Stir in the salt, pepper, nutmeg, 1 cup of the Gruyère, and all of the Parmesan. Taste it! This is the secret sauce, literally. Adjust seasoning if you like.
Arrange half of the sliced potatoes in the bottom of your buttered dish. Pour half of that incredible cream sauce over them. Repeat with the remaining potatoes and sauce.
Sprinkle the remaining 1 cup of Gruyère cheese evenly over the very top. This is what makes that gorgeous, golden crust.
Cover the dish tightly with foil. Bake for 45 minutes. Then, remove the foil and bake for another 25-30 minutes. You want the potatoes to be tender and the top to be bubbly and browned.
Take it out of the oven and let it rest for 15 minutes. I know it’s hard to wait, but this lets everything set up. Garnish with fresh thyme. Then, dig in!

Fun Variations to Try Next Time

Once you master the classic, play around! It’s your kitchen. Here are a few of my favorite twists.

Add about 6 ounces of diced ham or cooked, crumbled bacon between the layers. It becomes a full meal! So good. For another fantastic set-it-and-forget-it meal, check out my crockpot chicken potatoes and green beans.

Swap half the Yukon Golds for sweet potatoes. The color is stunning and the flavor is incredible.

Stir a tablespoon of whole grain or Dijon mustard into the cream sauce. It adds a wonderful little tang that cuts through the richness.

How to Store, Freeze, and Reheat

Got leftovers? Lucky you! Here’s how to keep the goodness going.

Let the dish cool completely. Cover tightly and store in the fridge for 3-4 days. Reheat individual portions in the microwave, or cover the whole dish with foil and warm it in a 350°F oven until hot.

You can freeze it after baking! Cool it, wrap it well in plastic and foil, and freeze for up to 2 months. Thaw in the fridge overnight and reheat, covered, in the oven.

NUTRITION INFORMATION

Calories: ~420 kcal
Carbohydrates: 35g
Protein: 15g
Fat: 25g
Saturated Fat: 15g
Cholesterol: 80mg
Sodium: 480mg
Fiber: 3g
Sugar: 7g

A Quick Q&A on This Recipe

I get asked these all the time! Here are the answers straight from my potato-loving heart.

Can I make this ahead of time?

Absolutely! Assemble the whole dish, cover it, and pop it in the fridge up to a day before you need it. Just add about 10 extra minutes to the baking time since it will be cold. Easy peasy.

What’s the best way to slice the potatoes?

A mandoline slicer is your best friend for this! It gives you perfect, even slices so everything cooks at the same rate. If you’re using a knife, just take your time and slice them as thin and evenly as you can.

My sauce seems thin. What did I do wrong?

Don’t panic! The flour needs a full 2 minutes of cooking in the butter to do its job. Also, make sure you bring the milk and cream to a good simmer so it thickens. It will continue to set up as it bakes and rests, I promise.

There you have it! My ultimate, go-to, never-fail recipe for the most incredible scalloped potatoes. It has never let me down. The creamy layers, that cheesy top, the sweet leeks… it’s pure happiness on a spoon. If you’re craving another creamy, potato-based comfort food, you’ll adore this French Style Creamy Potato and Leek Soup.

This dish is a total crowd-pleaser. It brings people together. It’s the definition of cozy elegance. I am so excited for you to make it and fall in love.

I can’t wait to hear how yours turns out! Please leave a comment and a rating below to let me know what you think!

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