Chicken, Leek and Butternut Squash Bake

Imagine sinking your fork into a golden-crusted, bubbling Chicken, Leek and Butternut Squash Bake that releases a cloud of fragrant steam. This comforting casserole combines tender chicken pieces with sweet butternut squash and silky leeks, all enveloped in a creamy sauce that’s both nourishing and indulgent. The Chicken, Leek and Butternut Squash Bake is the perfect weeknight solution when you crave something hearty yet wholesome. You’ll learn how to balance these flavors perfectly, create a velvety sauce without heavy cream, and assemble a dish that will quickly become a family favorite.

Why You’ll Love This Recipe

This Chicken, Leek and Butternut Squash Bake stands out as a true comfort food champion for several compelling reasons. The contrasting textures create a sensory delight: tender, juicy chicken chunks against the soft, melting leeks and the slight resistance of perfectly roasted butternut squash cubes. The sauce strikes the ideal balance between creamy richness and light enough to let the vegetables shine.

What makes this casserole truly special is its versatility. It’s elegant enough for dinner guests yet simple enough for Monday night dinner. Unlike many baked dishes that require constant attention, this recipe features a straightforward assembly process with minimal hands-on time. The combination of lean protein, fiber-rich vegetables, and moderate dairy makes it a more nutritious alternative to traditional cream-heavy casseroles.

The subtle sweetness from the butternut squash perfectly complements the gentle onion notes from the leeks, creating a harmonious flavor profile that appeals to even picky eaters. This chicken and vegetable bake might just become your new go-to comfort dish.

Ingredients

For this hearty Chicken, Leek and Butternut Squash Bake, you’ll need:

• 1.5 lbs (680g) boneless, skinless chicken breasts, cut into 1-inch chunks
• 1 medium butternut squash (about 2 lbs/900g), peeled and cut into 1-inch cubes
• 3 medium leeks (about 1 lb/450g), white and light green parts only, cleaned and sliced into half-moons
• 2 tablespoons olive oil, divided
• 2 tablespoons butter
• 3 garlic cloves, minced
• 2 tablespoons all-purpose flour
• 1¼ cups (300ml) chicken stock
• ¾ cup (180ml) half-and-half or light cream
• 1 tablespoon fresh thyme leaves (or 1 teaspoon dried)
• 1 teaspoon Dijon mustard
• 1 cup (100g) grated Gruyère or cheddar cheese
• ½ cup (50g) Panko breadcrumbs
• Salt and freshly ground black pepper to taste

The butternut squash provides natural sweetness, while leeks offer a milder, more delicate flavor than onions. Gruyère cheese adds a nutty depth, but cheddar works beautifully if that’s what you have on hand.

Pro Tips

Perfect your prep work: Cleaning leeks properly is crucial for this Chicken, Leek and Butternut Squash Bake. Slice them lengthwise, then into half-moons before soaking in cold water for 5 minutes. The grit will sink to the bottom, allowing you to lift out clean leeks. This prevents any unwanted grittiness in your finished dish.

Pre-roast your squash: For enhanced flavor, toss the butternut squash cubes with 1 tablespoon olive oil, salt, and pepper, then roast at 425°F (220°C) for 15 minutes before adding to the casserole. This caramelizes the natural sugars, creating deeper flavor and ensuring the squash cooks evenly with the chicken. This technique prevents the common problem of undercooked squash in baked dishes.

Create a proper roux: The secret to a silky-smooth sauce lies in your technique. When making the flour-butter mixture, cook it for at least 2 minutes until it smells slightly nutty but hasn’t browned. Add the liquid gradually while whisking constantly to prevent lumps. This foundation creates the perfect creamy texture that will coat every component of your chicken and vegetable bake without becoming gluey or separating during baking.

Instructions

Step 1

Preheat your oven to 375°F (190°C) and lightly grease a 9×13-inch baking dish. If you haven’t pre-roasted your butternut squash (see Pro Tips), toss the cubes with 1 tablespoon olive oil, ½ teaspoon salt, and ¼ teaspoon pepper. Spread on a baking sheet and roast for 15 minutes until edges begin to caramelize but squash isn’t fully tender.

Step 2

While the squash roasts, heat the remaining tablespoon of olive oil in a large skillet over medium-high heat. Season the chicken chunks with salt and pepper, then add to the hot pan. Cook for 4-5 minutes, turning occasionally, until just browned on the outside but not fully cooked through. Transfer the chicken to a plate and set aside.

Step 3

In the same skillet, melt the butter over medium heat. Add the cleaned, sliced leeks and cook for 5-6 minutes until softened but not browned. You’ll notice them becoming translucent and silky. Add the minced garlic and cook for another 30 seconds until fragrant, being careful not to let it burn.

Step 4

Sprinkle the flour over the leeks and stir constantly for 2 minutes to cook out the raw flour taste. Gradually whisk in the chicken stock, followed by the half-and-half, creating a smooth sauce. Bring to a gentle simmer and cook for 3-4 minutes until slightly thickened. Stir in the thyme leaves and Dijon mustard.

Step 5

Return the browned chicken to the skillet along with any accumulated juices. Add the roasted butternut squash and gently fold everything together until evenly coated in the sauce. Taste and adjust seasoning with salt and pepper as needed.

Step 6

Transfer the mixture to your prepared baking dish. Sprinkle evenly with the grated cheese, then top with Panko breadcrumbs. Bake your Chicken, Leek and Butternut Squash Bake for 25-30 minutes until bubbly around the edges and golden brown on top. Let stand for 5 minutes before serving to allow the sauce to set slightly.

Variations

Make it dairy-free: Transform this Chicken, Leek and Butternut Squash Bake into a dairy-free delight by substituting the butter with olive oil, the half-and-half with unsweetened coconut cream or cashew cream, and replacing the cheese with a sprinkle of nutritional yeast mixed into the breadcrumbs. This variation maintains the creamy texture while accommodating dairy allergies.

Vegetarian butternut squash and leek bake: Create a meatless version by replacing the chicken with 2 cups of cooked quinoa or 2 cans of drained white beans. Swap the chicken stock for vegetable broth. The protein alternatives absorb the delicious sauce while keeping the dish satisfying and hearty. This variation works beautifully for Meatless Mondays or vegetarian guests.

Spiced maple version: For a warming autumn twist, add ½ teaspoon each of ground cinnamon and nutmeg to the sauce, along with 1 tablespoon of maple syrup. This subtle sweetness enhances the natural flavors of the butternut squash and creates a cozy, seasonal chicken and vegetable casserole perfect for cool evenings.

Storage and Serving

This Chicken, Leek and Butternut Squash Bake stores beautifully in an airtight container in the refrigerator for up to 3 days. The flavors actually improve overnight as they meld together. Reheat individual portions in the microwave for 2-3 minutes or return the entire casserole (in an oven-safe dish) to a 350°F (175°C) oven for 15-20 minutes until heated through.

For freezing, cool the bake completely, then portion into freezer-safe containers. It will keep for up to 3 months. Thaw overnight in the refrigerator before reheating.

Serve this comforting casserole alongside a crisp green salad dressed with a simple vinaigrette to cut through the richness. For a heartier meal, pair it with crusty whole grain bread for soaking up the delicious sauce. For an elegant presentation, sprinkle with additional fresh thyme leaves and a few toasted pumpkin seeds just before bringing it to the table.

FAQs

Can I prepare this chicken bake ahead of time?
Yes! Assemble the Chicken, Leek and Butternut Squash Bake up to the point of baking, cover tightly, and refrigerate for up to 24 hours. When ready to serve, remove from the refrigerator 30 minutes before baking, then bake as directed, adding 5-10 minutes to the cooking time.

Can I use frozen butternut squash instead of fresh?
Absolutely. Use 4 cups of frozen butternut squash cubes, but don’t thaw them first. Roast them from frozen (they’ll need a few extra minutes) or add them directly to the sauce mixture. They’ll release more moisture, so you might want to reduce the chicken stock by ¼ cup.

What can I substitute for leeks?
If leeks aren’t available, use 2 medium yellow onions or 4 large shallots, thinly sliced. The flavor will be slightly different but still delicious in this chicken and squash casserole.

Is this recipe gluten-free?
Not as written, but you can easily make it gluten-free by substituting the all-purpose flour with cornstarch (use 1 tablespoon instead of 2) and replacing the Panko with gluten-free breadcrumbs or crushed rice crackers.

Can I add other vegetables to this bake?
Certainly! Baby spinach, peas, or diced bell peppers make excellent additions. Add spinach or peas during the last minute of cooking the sauce, or sauté diced bell peppers with the leeks for a colorful twist on this Chicken, Leek and Butternut Squash Bake.

Conclusion

This Chicken, Leek and Butternut Squash Bake is comfort food at its finest — a golden, bubbling casserole that combines tender chicken, sweet butternut squash, and silky leeks in a creamy, herb-infused sauce. It’s the kind of dish that brings everyone to the table with eager anticipation and leaves them feeling satisfied yet not overwhelmed. Whether you’re cooking for a cozy family dinner or looking to impress weekend guests, this versatile bake delivers on flavor, texture, and visual appeal. The combination of wholesome ingredients makes it a more nutritious alternative to traditional cream-heavy casseroles while still providing that essential comfort food experience we all crave.

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