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Butternut Lasagna With Celeriac, Mushrooms, and Leeks

There’s something profoundly comforting about lasagna, isn’t there? For me, it’s inextricably linked to autumn. I remember crisp October evenings spent in my grandmother’s kitchen, the air thick with the aroma of roasting squash and simmering herbs. The bubbling, golden-brown top of her butternut lasagna was always a welcome sight, a promise of warmth and shared laughter around the table. This recipe, inspired by those cherished memories, takes a slightly different route, incorporating the earthy depth of celeriac and the savory richness of mushrooms and leeks to create a truly unforgettable dish.

Recipe Overview

Prep Time: 30 minutes
Cook Time: 60 minutes
Total Time: 1 hour 30 minutes
Servings: 8
Yield: One 9×13 inch lasagna
Dietary Type: Vegetarian (can be adapted to vegan – see variations below)

Ingredients

1 butternut squash, roasted and scooped out
2 leeks, chopped
1 celeriac stalk, peeled and chopped
8 ounces cremini mushrooms, sliced
1 (9 ounce) box lasagna noodles
2 garlic cloves, diced
3 tablespoons butter
2 tablespoons flour
3⁄4 cup heavy cream
3⁄4 cup vegetable broth, plus a little extra
8 ounces cheese, shredded (I like an Italian mix…Swiss or white cheddar might also be good)
1 teaspoon salt
Italian seasoning (I use Tuscan Sunset by Penzy’s)
French tarragon

Equipment Needed

9×13 inch baking dish
Large pan or skillet
Small saucepan
Whisk
Vegetable peeler
Cutting board
Knife

Instructions

Preheat your oven according to your butternut squash roasting preference (often 400F/200C). Halve the butternut squash, remove the seeds, and roast until tender. Once cooled, scoop out the flesh and set aside.
Begin by making a roux. In a small saucepan, melt 2 tablespoons of butter over medium heat. Add 2 tablespoons of flour and whisk constantly for 1-2 minutes until a smooth paste forms. This is your roux. Set aside.
In a large pan or skillet, melt the remaining 1 tablespoon of butter over medium heat. Add the chopped leeks, peeled and chopped celeriac, and sliced cremini mushrooms.
Sauté the vegetables until they are tender and slightly softened, approximately 8-10 minutes. Add the diced garlic during the last minute of cooking, being careful not to burn it.
Season the sautéed vegetables with 1/2 teaspoon of salt, Italian seasoning to taste (about 1/2 teaspoon), and French tarragon to taste (about 1/4 teaspoon). Stir to combine the seasonings evenly.
Now, return to the roux you prepared earlier. Over medium heat, gradually whisk in the 3/4 cup of heavy cream, ensuring there are no lumps.
Add the remaining 1/2 teaspoon of salt, and another 1/4 teaspoon each of Italian seasoning and French tarragon to the sauce.
Cook the cream sauce, stirring constantly, until it becomes bubbly and thickens, about 3-5 minutes.
Stir in the 3/4 cup of vegetable broth into the thickened cream sauce. This will thin it out slightly to a good lasagna consistency.
Preheat your oven to 350°F (175°C).
Pour a little extra vegetable broth into the bottom of a 9×13 inch baking dish. This will help prevent the lasagna noodles from sticking.
Place a layer of lasagna noodles in the baking dish, overlapping as necessary to cover the bottom. You may need to break some noodles to fit.
Mash or coarsely chop the roasted butternut squash so that it can be easily spread. Layer the squash on top of the noodles, creating a layer that is approximately 1/4 to 1/2 inch thick.
Pour 1/3 of the cream sauce over the butternut squash layer, spreading it evenly.
Add another layer of lasagna noodles on top of the sauced butternut squash.
Layer the sautéed vegetables (leeks, celeriac, and mushrooms) onto this layer of noodles, distributing them evenly.
Pour another 1/3 of the cream sauce over the vegetable layer, spreading it evenly.
Add the final layer of lasagna noodles.
Pour the remaining cream sauce over the final layer of noodles, ensuring they are well covered.
Top the lasagna with the shredded cheese, distributing it evenly across the surface.
Bake in the preheated oven at 350°F (175°C) until the lasagna is golden brown and bubbly throughout, approximately 45-60 minutes. A knife inserted into the center should come out hot. If the top is browning too quickly, you can loosely tent it with foil for the last 15-20 minutes of baking.
Let the lasagna rest for at least 10-15 minutes before cutting and serving. This allows the layers to set slightly and makes it easier to slice.

Expert Tips & Tricks

Roasting the butternut squash ahead of time can save you precious minutes on the day you plan to assemble the lasagna.
For a more intense flavor, try using dried porcini mushrooms in addition to the cremini. Soak them in hot water for 30 minutes, then chop and add them to the sauteed vegetables. Be sure to reserve the soaking liquid and add it to the sauce for extra depth.
If you find that your cream sauce is too thick, add a splash more vegetable broth to thin it out to your desired consistency.
Don’t overcrowd the pan when sautéing the vegetables. Cook them in batches if necessary to ensure they brown evenly and don’t steam.
To prevent the noodles from sticking together while assembling, lay them out on a clean surface and brush them lightly with olive oil.
If the top of the lasagna is browning too quickly during baking, tent it loosely with aluminum foil.

Serving & Storage Suggestions

Serve the butternut lasagna warm, ideally after allowing it to rest for 10-15 minutes after baking. This allows the layers to set and makes slicing easier. A simple green salad with a light vinaigrette makes a wonderful accompaniment.

Leftover lasagna can be stored in the refrigerator for up to 3-4 days. Allow the lasagna to cool completely before covering it tightly with plastic wrap or transferring it to an airtight container.

To reheat, preheat your oven to 350°F (175°C). Place the lasagna in an oven-safe dish, cover it with foil, and bake for 20-30 minutes, or until heated through. You can also reheat individual slices in the microwave, but the texture may be slightly softer.

For longer storage, lasagna can be frozen for up to 2-3 months. Wrap individual slices tightly in plastic wrap and then place them in a freezer-safe bag or container. Thaw in the refrigerator overnight before reheating.

Nutritional Information

Nutrient	Amount per Serving	% Daily Value
Calories	420 kcal	21%
Total Fat	20.3g	31%
Saturated Fat	12.4g	62%
Cholesterol	60.2mg	20%
Sodium	625.4mg	26%
Total Carbohydrate	49.6g	17%
Dietary Fiber	4.5g	16%
Sugars	5.4g	–
Protein	13g	26%

Note: Nutritional information is an estimate and can vary based on specific ingredients and portion sizes.

Variations & Substitutions

Vegan: Substitute the heavy cream with full-fat coconut milk or cashew cream. Use vegan butter for the roux and omit the cheese, or use a plant-based shredded cheese alternative. Ensure your lasagna noodles are egg-free.
Gluten-Free: Use gluten-free lasagna noodles. You may need to adjust the baking time slightly.
Spicier: Add a pinch of red pepper flakes to the sautéed vegetables for a subtle kick.
Different Vegetables: Feel free to substitute other root vegetables like parsnips or carrots for the celeriac. Spinach or kale can also be added to the vegetable layer.
Cheese Variations: Try using Gruyere, Fontina, or a smoked Gouda for a different flavor profile.

FAQs (Frequently Asked Questions)

Q: Can I assemble the lasagna ahead of time?
A: Yes, you can assemble the lasagna up to 24 hours in advance. Cover it tightly with plastic wrap and store it in the refrigerator. Add about 15 minutes to the baking time.

Q: Do I need to pre-cook the lasagna noodles?
A: It depends on the brand of noodles you’re using. Some brands are “oven-ready” and do not require pre-cooking. Follow the instructions on the package. If your noodles are not oven-ready, pre-cook them according to package directions before assembling the lasagna.

Q: Can I use a different type of squash?
A: Yes, other types of winter squash such as acorn squash or Hubbard squash can be used as a substitute for butternut squash. The flavor will be slightly different, but still delicious.

Q: How can I prevent the lasagna from being too watery?
A: Make sure to drain the roasted butternut squash well and avoid overcooking the vegetables, as they will release moisture. Also, be sure to let the lasagna rest for at least 10-15 minutes after baking, which allows the layers to set.

Q: What’s the best cheese to use for this lasagna?
A: A blend of Italian cheeses like mozzarella, provolone, and Parmesan works well. You can also use Swiss or white cheddar for a milder flavor. Experiment with your favorite cheeses!

Final Thoughts

This butternut lasagna with celeriac, mushrooms, and leeks is more than just a recipe; it’s an invitation to create memories. Gather your loved ones, fill your kitchen with the intoxicating aroma of roasted squash and savory vegetables, and embark on this culinary adventure. Don’t be afraid to experiment with variations, make it your own, and most importantly, share the delicious results. I’d love to hear about your experiences, so please feel free to share your feedback and photos. Pair this lasagna with a crisp white wine or a cozy glass of mulled cider for the perfect autumnal meal. Happy cooking!

Butternut Lasagna With Celeriac, Mushrooms, and Leeks Recipe