Air Fryer Leek Christmas Casserole
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Air Fryer Leek Christmas Casserole saves you from heating up the whole kitchen during the holidays while still giving you that golden, bubbling cheese top everyone loves. The leeks cook down until they’re sweet and tender, coated in melted Gouda that clings to every piece. Fast, creamy, and no oven space needed. It’s the side dish that makes hosting easier.
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I make this for Christmas dinner, holiday potlucks, and family gatherings because it’s the kind of creamy comfort food that feeds a crowd, travels well, and comes together quickly. It’s perfect for make-ahead meals since it stays fresh in the fridge for up to 3 days and reheats beautifully without losing any richness.
Ingredients You’ll Need
You’ll need all the ingredients shown in the photograph below.
How to Make Air Fryer Leek Christmas Casserole with Step-By-Step Instructions
Scroll down for the full recipe card containing a full printable recipe and measurements in both US customary and metric units.
Let me walk you through making this creamy, cheesy casserole that’ll become your new favorite holiday side dish.
Prep the Leeks and Cornstarch Mixture
Thinly slice the leeks and rinse them well since dirt hides between the layers. For extra depth and richness, add one finely chopped red onion and a little diced red or yellow bell pepper for subtle sweetness and color that won’t overpower the leeks.
In a small bowl, stir the cornstarch into ¼ cup of milk until smooth, then set it aside. For the best texture, use whole milk; it gives the sauce balanced creaminess without feeling too heavy.
A great whisk smooths out any remaining cornstarch lumps while keeping the mixture silky.
Cook the Leeks Until Soft and Buttery
After preheating a large pot or a deep pan to medium-high heat, add the butter. Once melted, add the sliced leeks and veggies and cook for about 15 minutes, stirring often to prevent sticking.
In the last couple of minutes, stir in a bit of chopped fresh spinach so it wilts and adds color and a mild earthy note to the creamy leeks. They’ll soften and turn creamy as they release moisture and draw in the butter, becoming almost translucent and incredibly tender when done
Add the Cream Sauce and Cheese
Pour in the cornstarch mixture, the remaining milk, and the shredded Gouda, then season with salt and black pepper. Stir for about 5 minutes until the Gouda melts and the sauce thickens.
The cornstarch will transform the milk into a velvety coating that clings to every piece of leek. I love using my silicone spatula for this step because it makes it easy to scrape down the sides and keep everything incorporated.
Assemble and Air Fry the Casserole
Transfer the creamy leek mixture and any add-ins to a casserole dish that fits in your air fryer basket. Top evenly with the shredded Parmesan cheese, making sure to cover the entire surface so you get that golden crust everywhere.
Place the dish in the air fryer and cook at 325°F (160ºC) for 15 minutes, or until the top is bubbly and lightly browned. Use oven mitts when removing the hot dish from the air fryer.
Optional: If your air fryer has a broil or top-heat setting, broil the casserole for the last 2-3 minutes to crisp and deepen the golden Parmesan topping. Watch it closely to prevent burning.
Garnish and Serve
Let the casserole cool at room temperature for a few minutes so the sauce can set and the slices hold together, and lastly sprinkle fresh parsley on top before serving to add a bright pop of color and a fresh note that balances the rich cheese and butter. Enjoy!
Equipment
Ingredients
- 6 leek
- ¼ cup butter
- 4 tablespoons cornstarch
- 1 ½ cup milk
- 1 cup gouda cheese shredded
- Salt and pepper
- 1 ½ cup parmesan cheese
- Fresh parsley to serve
Instructions
- Thinly slice the leek. Mix the cornstarch with ¼ cup of milk.4 tablespoons cornstarch, 1 ½ cup milk
- Heat a big pot to medium-high and add the butter. Cook until it melts.¼ cup butter
- Add the leek and cook – stirring constantly – for about 15 minutes, the leek should be soft and creamy.6 leek
- Add the cornstarch and milk mixture, the rest of the milk, gouda cheese, salt and pepper.1 cup gouda cheese, Salt and pepper
- Mix well and cook for 5 more minutes.
- Transfer the mixture to a casserole dish and top with the parmesan cheese. Bake in the air fryer at 325°F (160ºC) for 15 minutes, or until bubbly.1 ½ cup parmesan cheese
- Serve with fresh parsley.Fresh parsley
Notes
- Clean the leeks thoroughly: Slice them lengthwise before cutting and rinse under cold water to remove any hidden dirt between the layers.
- Don’t skip mixing the cornstarch with cold milk first: Always mix the cornstarch with ¼ cup of cold milk before adding it to the hot liquid to prevent lumps and create a smooth, creamy sauce.
- Stir constantly during the 15-minute cook: Keep the leeks moving while cooking to prevent sticking and help them cook evenly into a silky texture.
- Use a casserole dish that fits your air fryer: Measure your air fryer basket and choose a dish with enough space around the sides to allow air circulation for an evenly browned top.
- Let it rest for 5 minutes after air frying: The casserole comes out bubbling hot, so let it rest briefly to let the sauce set and keep it from running on your plate.
- Flash freeze before storing: If freezing, let the casserole cool completely, then freeze uncovered for 1 hour before wrapping tightly to prevent condensation and ice crystals.
Nutrition
How to Store Leftovers
Store leftovers in an airtight container in the fridge for up to 3 days.
The casserole reheats beautifully in the oven at 350°F for about 10 minutes, wrapped in foil to maintain moisture, or at a lower temperature of 300°F in the air fryer for around 5 minutes for small portions until warm and bubbly.
A splash of milk helps bring back the creaminess in large servings, as the leeks stay tender and the cheese sauce turns smooth again.
What to Serve With Air Fryer Leek Christmas Casserole
I love pairing this casserole with roasted turkey, ham steaks, prime rib, or roasted chicken since the creamy leeks balance rich, savory meats beautifully. The mild, buttery flavor also works perfectly alongside glazed ham or herb-crusted pork tenderloin for Christmas dinner.
For a complete holiday spread, serve it with roasted Brussels sprouts, green beans, cranberry sauce, dinner rolls, and mashed potatoes. The soft, cheesy texture contrasts nicely with crispy roasted vegetables, and the Gouda adds enough richness to hold its own next to any main course on your holiday table.
More Easy Recipes for You to Try at Home
You’ll want to try these other air fryer casseroles that are just as comforting and perfect for make-ahead meals.
