When the weather calls for something warm, comforting, and deeply satisfying, this Loaded Sweet Potato Lasagna with Feta, Sage, Walnuts & Brown Butter Drizzle is the perfect dish to bring to the table.
Instead of the traditional tomato-based lasagna, this cozy version combines thinly sliced sweet potatoes with creamy ricotta, salty feta, mozzarella, Parmesan, tender spinach, garlic, and herbs. The result is a rich and hearty vegetarian lasagna with layers of creamy, cheesy goodness and naturally sweet roasted sweet potato.
The finishing touch is what makes this dish especially special: a warm brown butter drizzle infused with fresh sage and toasted walnuts. The nutty butter, crispy sage, and crunchy walnuts complement the creamy lasagna beautifully.
Ingredients
For the Lasagna
- 2 large sweet potatoes, peeled and thinly sliced
- 9 lasagna noodles
- 2 tablespoons olive oil
- 1 medium yellow onion, diced
- 3 cloves garlic, minced
- 5 ounces fresh spinach
- 15 ounces ricotta cheese
- 1 cup crumbled feta cheese
- 1 cup shredded mozzarella cheese
- 1/2 cup grated Parmesan cheese
- 1 teaspoon dried oregano
- 1/2 teaspoon ground nutmeg
- Salt, to taste
- Black pepper, to taste
- 1 cup vegetable broth
- 2 tablespoons fresh sage, chopped
For the Brown Butter Drizzle
- 6 tablespoons unsalted butter
- 1 tablespoon fresh sage leaves, chopped
- 1/3 cup walnuts, roughly chopped
- Pinch of salt
Instructions
1. Prepare the Oven and Baking Dish
Preheat your oven to 375°F (190°C).
Lightly grease a 9×13-inch baking dish with olive oil and set it aside.
2. Cook the Lasagna Noodles
Bring a large pot of salted water to a boil.
Cook the lasagna noodles according to the package directions until they are just tender. Avoid overcooking them because they will continue cooking in the oven.
Drain the noodles and arrange them separately so they don’t stick together.
3. Prepare the Sweet Potatoes
Peel the sweet potatoes and slice them very thinly and evenly.
Thin slices are important because the sweet potatoes need enough time to become tender while the lasagna bakes.
If your sweet potatoes are particularly thick, use a mandoline carefully to create uniform slices.
4. Prepare the Spinach and Cheese Filling
Heat the olive oil in a large skillet over medium heat.
Add the diced onion and cook for 4–5 minutes, stirring occasionally, until softened and lightly golden.
Add the minced garlic and cook for another minute, until fragrant.
Add the fresh spinach and cook until wilted, stirring occasionally.
Remove the skillet from the heat.
Stir in the ricotta cheese, feta cheese, oregano, nutmeg, salt, black pepper, and chopped fresh sage.
Mix until the ingredients are evenly combined.
5. Build the Lasagna
Spread a thin layer of the spinach and cheese mixture over the bottom of the prepared baking dish.
Arrange a layer of thinly sliced sweet potatoes over the filling.
Add a layer of lasagna noodles.
Spread another portion of the ricotta-spinach mixture over the noodles.
Continue layering the sweet potatoes, noodles, and creamy filling until the ingredients are used.
Try to finish with a layer of noodles and creamy filling rather than leaving exposed sweet potato slices on top.
Pour the vegetable broth slowly around the edges of the baking dish. This provides additional moisture to help the sweet potatoes become tender during baking.
6. Add the Cheese Topping
Sprinkle the shredded mozzarella and grated Parmesan evenly over the top.
Cover the baking dish tightly with aluminum foil.
7. Bake
Place the covered lasagna in the preheated oven and bake for approximately 35 minutes.
Remove the foil and continue baking for another 15–20 minutes, or until the lasagna is bubbling and the cheese is melted and golden.
If you want a more deeply browned top, you can briefly place it under the broiler at the end, watching carefully.
8. Make the Brown Butter Sage and Walnut Drizzle
While the lasagna is baking, prepare the topping.
Place the butter in a small skillet over medium heat.
Allow it to melt and continue cooking until it begins to foam. As it cooks, the milk solids will gradually turn golden brown and develop a nutty aroma.
Watch the butter closely because it can go from beautifully browned to burnt quickly.
Add the chopped fresh sage and walnuts.
Cook for approximately 1–2 minutes, stirring gently, until the sage is fragrant and the walnuts are lightly toasted.
Add a small pinch of salt and immediately remove the skillet from the heat.
9. Rest and Serve
Remove the lasagna from the oven and let it rest for approximately 10 minutes before slicing.
This resting time allows the layers to settle, making the lasagna easier to cut and serve.
Cut into portions and drizzle each serving generously with the warm brown butter, sage, and walnut mixture.
Tips for the Best Sweet Potato Lasagna
Slice the sweet potatoes thinly
Thin, even slices are essential. Thick pieces may remain firm while the rest of the lasagna is fully cooked.
Don’t skip the resting time
Allowing the lasagna to rest for 10 minutes helps the creamy layers set slightly and makes serving much easier.
Watch the brown butter
Brown butter develops a wonderful nutty flavor, but it can burn quickly. Once the butter turns golden and smells toasted, add the sage and walnuts and remove it from the heat shortly afterward.
Use freshly grated Parmesan
Freshly grated Parmesan melts and browns beautifully and gives the topping a richer flavor.
Don’t overfill the dish
Keep the layers reasonably even so the lasagna cooks consistently from the center to the edges.
Make It Ahead
This lasagna is a great make-ahead meal.
Assemble the lasagna, cover it tightly, and refrigerate it before baking. When ready to cook, allow it to sit at room temperature briefly while the oven preheats, then bake until hot and bubbling.
The brown butter topping is best prepared shortly before serving rather than in advance.
Serving Suggestions
Serve this cozy lasagna with a simple side salad or roasted vegetables.
It also pairs beautifully with:
- Arugula salad
- Mixed green salad
- Roasted Brussels sprouts
- Garlic bread
- Steamed green beans
- Roasted carrots
- Sautéed mushrooms
Because the lasagna is rich and creamy, a crisp salad with a light vinaigrette makes a particularly refreshing side.
Variations
Add Mushrooms
Sauté sliced mushrooms with the onion and garlic before adding the spinach for an earthier flavor.
Add Kale
Replace some or all of the spinach with finely chopped kale. Cook it until tender before mixing it with the cheeses.
Make It Spicier
Add a pinch of crushed red pepper flakes to the spinach and ricotta mixture.
Add More Herbs
Fresh thyme or rosemary can be added alongside the sage for an even more aromatic flavor.
Nut-Free Version
Simply leave the walnuts out of the brown butter topping. The sage brown butter will still provide plenty of flavor.
Storage
Store leftover lasagna in an airtight container in the refrigerator for up to 3–4 days.
Reheat individual portions in the microwave or cover with foil and warm in a 350°F (175°C) oven until heated through.
For the best texture, prepare fresh brown butter sage topping when reheating leftovers.
Freezing
The assembled lasagna can be frozen before baking. Wrap the baking dish tightly with plastic wrap followed by aluminum foil and freeze.
When ready to cook, thaw it in the refrigerator before baking.
You can also freeze individual cooked portions for convenient future meals.
Recipe at a Glance
Prep Time: 25 minutes
Cooking Time: 55 minutes
Total Time: 1 hour 20 minutes
Servings: 8
Approximate Calories: 560 per serving
Final Thoughts
This Loaded Sweet Potato Lasagna with Feta, Sage, Walnuts & Brown Butter Drizzle is a beautiful twist on classic lasagna. Sweet potatoes bring natural sweetness and heartiness, while ricotta, feta, mozzarella, and Parmesan create rich and creamy layers.
The brown butter, fresh sage, and toasted walnuts take the dish to another level, adding a warm nutty aroma and a satisfying contrast of textures.
It is the kind of cozy, impressive vegetarian meal that feels perfect for autumn dinners, holiday gatherings, or any night when you want something a little more special than ordinary lasagna.