Homemade Scalloped Potatoes with Leeks

If you ask me, scalloped potatoes get even better when you add leeks.

This classic side dish combines tender potato slices with mild, sweet leeks in a creamy sauce that’s hard to resist. The butter and garlic create a savory base, while fresh thyme adds just the right amount of earthiness.

It’s baked until the potatoes are soft and the top gets a little golden. A hint of nutmeg in the cream sauce brings everything together in a way that feels both comforting and a bit fancy.

It’s the kind of dish that works for Sunday dinner or a holiday table, but it’s easy enough to make any night of the week.

What Kind of Potatoes Should I Use?

For scalloped potatoes, you’ll want to reach for starchy potatoes like Russets or Yukon Golds, which are my top picks for this recipe. Russets will give you a creamier, more tender result since they absorb the milk and cream beautifully, while Yukon Golds hold their shape a bit better and add a buttery flavor. Avoid waxy potatoes like red potatoes or fingerlings, as they won’t break down enough to create that classic creamy texture you’re looking for. Whatever you choose, try to pick potatoes that are similar in size so they cook evenly, and slice them about 1/8-inch thick for the best results.

Options for Substitutions

This recipe is pretty forgiving, so here are some swaps you can make if needed:

• Leeks: If you can’t find leeks, yellow or sweet onions work great as a substitute. Use about 1 cup of thinly sliced onions. You could also try shallots for a milder, slightly sweeter flavor.
• Cream: Heavy cream gives the richest result, but you can use half-and-half if that’s what you have. For a lighter version, try using all milk instead, though the sauce won’t be quite as thick or rich.
• Milk and cream combination: If you want to skip dairy altogether, unsweetened oat milk or cashew cream can work, though the flavor will be different. You might need to add a bit of cornstarch to help thicken the sauce.
• Potatoes: Russet potatoes are traditional for scalloped potatoes and shouldn’t be substituted – their starch content helps thicken the sauce and creates that classic creamy texture. Yukon golds can work in a pinch, but avoid waxy red potatoes as they won’t give you the same result.
• Fresh thyme: Dried thyme works fine here – just use about 1/3 teaspoon since dried herbs are more concentrated. Rosemary is another nice option if you prefer that flavor.

Watch Out for These Mistakes While Baking

The biggest mistake with scalloped potatoes is slicing them unevenly, which leads to some pieces turning mushy while others stay hard – aim for uniform 1/8-inch slices using a mandoline or sharp knife for consistent cooking.

Another common error is skipping the step of simmering the cream mixture before adding the potatoes, as this pre-thickening prevents a watery casserole and ensures a creamy sauce that coats every layer.

To avoid a dried-out top layer, cover your baking dish with foil for the first 45 minutes, then remove it for the final 15 minutes to get that golden-brown finish.

Don’t rush the resting time after baking – let the dish sit for at least 10 minutes so the sauce can set properly, making it much easier to serve neat portions instead of a runny mess.

What to Serve With Scalloped Potatoes?

Scalloped potatoes are pretty rich and creamy, so they pair really well with simple roasted or grilled proteins like chicken, pork chops, or a nice steak. I love serving them alongside a basic green salad with a light vinaigrette to balance out all that creaminess from the dish. If you’re going for a full comfort meal, roasted vegetables like green beans, asparagus, or Brussels sprouts make great side dishes that won’t compete with the potatoes. You could also serve them with glazed ham during the holidays – the salty-sweet combo works perfectly with the mild, creamy potatoes and leeks.

Storage Instructions

Store: Leftover scalloped potatoes keep really well in the fridge. Just cover the dish tightly with foil or transfer to an airtight container, and they’ll stay good for up to 4 days. The flavors actually get even better the next day as everything melds together.

Freeze: You can freeze scalloped potatoes, though the texture might change slightly when thawed. Let them cool completely, then wrap the dish tightly in plastic wrap and foil, or portion into freezer containers. They’ll keep for up to 2 months in the freezer.

Reheat: To warm up your scalloped potatoes, cover with foil and bake at 350°F for about 20-25 minutes until heated through. You can also microwave individual portions, but the oven method keeps them creamier and prevents the edges from drying out.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 1400-1600
• Protein: 25-30 g
• Fat: 50-60 g
• Carbohydrates: 210-230 g

Ingredients

For the cream sauce:

• 3 tbsp butter (I like Kerrygold unsalted butter for this)
• 1.25 cups leeks (white and light green parts only)
• 3 garlic cloves
• 1.5 tsp thyme
• 1 cup milk
• 1 cup heavy cream (I use Horizon Organic for a richer sauce)
• 2.5 tsp salt
• 0.75 tsp pepper (freshly ground preferred for more flavor)
• 1 pinch nutmeg

For the base:

• 2.5 lb potatoes (peeled and sliced into 1/8-inch rounds)

Step 1: Prepare Potatoes and Preheat Oven

• 2.5 lb potatoes, peeled and sliced into 1/8-inch rounds
• 1 tbsp butter

Peel the potatoes and slice them into 1/8-inch rounds—I recommend using a mandoline slicer for consistency, which ensures even cooking throughout the dish.

Place the sliced potatoes in a bowl of cold water to prevent browning while you prepare the other components.

Preheat your oven to 350°F and lightly butter a 9×13-inch baking dish (or similar size casserole).

Step 2: Prepare the Aromatics

• 1.25 cups leeks, sliced
• 3 garlic cloves, minced
• 1.5 tsp thyme

While the oven preheats, prepare your leeks by trimming the dark green tops and roots, then slicing them into thin half-moons, using only the white and light green parts.

Mince the garlic cloves finely.

Measure out your thyme.

This mise en place ensures everything is ready when you start cooking the sauce.

Step 3: Build the Sauce Base

• 2 tbsp butter
• 1.25 cups leeks, sliced
• 3 garlic cloves, minced
• 1.5 tsp thyme

Melt the remaining 2 tablespoons of butter in a large saucepan over medium heat.

Add the sliced leeks and cook for about 2 minutes, stirring occasionally, until they begin to soften.

Add the minced garlic and thyme, cooking for just 30 seconds until fragrant—this short cooking time prevents the garlic from becoming bitter while releasing its flavor into the butter.

Step 4: Create the Cream Sauce

• 1 cup milk
• 1 cup heavy cream
• 2.5 tsp salt
• 0.75 tsp pepper
• 1 pinch nutmeg

Pour in the milk and heavy cream, stirring to combine with the leek mixture.

Add the salt, pepper, and nutmeg.

Bring the mixture to a boil over medium-high heat, then reduce the heat to medium-low and simmer for about 5 minutes, stirring occasionally, until the sauce thickens slightly—it should coat the back of a spoon.

I find that letting it simmer allows the flavors to meld beautifully and the sauce to develop the right consistency for coating the potatoes.

Step 5: Assemble and Bake

• potatoes from Step 1, drained and patted dry
• cream sauce from Step 4
• prepared baking dish from Step 1

Drain the potatoes from their cold water bath and pat them dry with paper towels—this step is important because excess moisture can make the dish watery.

Add the drained potatoes to the hot cream sauce, stirring gently to coat all the slices evenly.

Transfer the potato and leek mixture to the prepared baking dish, spreading it into an even layer.

Bake uncovered at 350°F for approximately 1 hour, until the potatoes are completely tender when pierced with a fork and the top is lightly golden.

Homemade Scalloped Potatoes with Leeks

Delicious Homemade Scalloped Potatoes with Leeks recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 30 minutes mins

Cook Time 1 hour hr

Total Time 1 hour hr 30 minutes mins

Servings 7 servings

Calories 1500 kcal

Ingredients

  

For the cream sauce::

• 3 tbsp butter (I like Kerrygold unsalted butter for this)
• 1.25 cups leeks (white and light green parts only)
• 3 garlic cloves
• 1.5 tsp thyme
• 1 cup milk
• 1 cup heavy cream (I use Horizon Organic for a richer sauce)
• 2.5 tsp salt
• 0.75 tsp pepper (freshly ground preferred for more flavor)
• 1 pinch nutmeg

For the base::

• 2.5 lb potatoes (peeled and sliced into 1/8-inch rounds)

Instructions

 

• Peel the potatoes and slice them into 1/8-inch rounds—I recommend using a mandoline slicer for consistency, which ensures even cooking throughout the dish. Place the sliced potatoes in a bowl of cold water to prevent browning while you prepare the other components. Preheat your oven to 350°F and lightly butter a 9x13-inch baking dish (or similar size casserole).
• While the oven preheats, prepare your leeks by trimming the dark green tops and roots, then slicing them into thin half-moons, using only the white and light green parts. Mince the garlic cloves finely. Measure out your thyme. This mise en place ensures everything is ready when you start cooking the sauce.
• Melt the remaining 2 tablespoons of butter in a large saucepan over medium heat. Add the sliced leeks and cook for about 2 minutes, stirring occasionally, until they begin to soften. Add the minced garlic and thyme, cooking for just 30 seconds until fragrant—this short cooking time prevents the garlic from becoming bitter while releasing its flavor into the butter.
• Pour in the milk and heavy cream, stirring to combine with the leek mixture. Add the salt, pepper, and nutmeg. Bring the mixture to a boil over medium-high heat, then reduce the heat to medium-low and simmer for about 5 minutes, stirring occasionally, until the sauce thickens slightly—it should coat the back of a spoon. I find that letting it simmer allows the flavors to meld beautifully and the sauce to develop the right consistency for coating the potatoes.
• Drain the potatoes from their cold water bath and pat them dry with paper towels—this step is important because excess moisture can make the dish watery. Add the drained potatoes to the hot cream sauce, stirring gently to coat all the slices evenly. Transfer the potato and leek mixture to the prepared baking dish, spreading it into an even layer. Bake uncovered at 350°F for approximately 1 hour, until the potatoes are completely tender when pierced with a fork and the top is lightly golden.