Veggie Pesto & Spinach Lasagna

There are few things as comforting, cozy, and crowd-pleasing as a bubbling tray of lasagna. This Veggie Pesto & Spinach Lasagna brings a bright, herb-forward twist to the classic dish. Layers of tender lasagna sheets, a creamy basil-pesto béchamel, and wilted spinach coalesce into a slice that’s fresh, satisfying, and perfect for weeknight dinners or weekend entertaining.

Before we dive in, note that this recipe uses simple, pantry-friendly ingredients: onion, spinach, butter, flour, whole milk, basil pesto, parmesan, lasagna sheets, and a drizzle of olive oil. The techniques are approachable, and the result is a show-stopping vegetarian lasagna that still feels indulgent thanks to a silky, cheese-flecked sauce.

Why you’ll love this Veggie Pesto & Spinach Lasagna

• Bright flavor from a generous amount of basil pesto blended straight into the béchamel.
• Easy layers using dried lasagna sheets—no boiling required if your sheets are oven-ready, but the method below works well either way.
• A great make-ahead dish that reheats beautifully; it also freezes well for future meals.
• Ingredient-focused: the spinach and onion provide texture and body while the parmesan gives the whole dish umami and richness.

Ingredients

Use the following measured ingredients exactly as listed to achieve the best results.

• 1 large onion, finely chopped
• 600 g spinach, coarsely chopped
• 100 g butter
• 100 g flour
• 1 l whole milk
• 300 g basil pesto
• 100 g parmesan + extra for sprinkling
• 1 packet of lasagna sheets
• salt
• pepper
• olive oil

Equipment you’ll need

• Large sauté pan
• Medium saucepan
• Wooden spoon or spatula
• Whisk
• Large baking dish (about 9×13 inches or similar)
• Knife and cutting board
• Measuring scales and spoons

Taste and texture notes

The sauce here is closer to a pesto-infused béchamel—silky, lightly thickened, and studded with parmesan for depth. The spinach wilts down to a tender, verdant layer that contrasts with the soft chew of the lasagna sheets. A final sprinkle of extra parmesan and a little olive oil before baking produces a nicely browned top with a savory crust.

Step-by-step Instructions

The following directions have been rewritten into clear, actionable steps while keeping the same order and ingredient quantities as the original. Read through once before you start; mise en place makes this assembly smooth.

1. Prepare the vegetables:
   • Heat a drizzle of olive oil in a large sauté pan over medium heat.
   • Add the 1 large onion, finely chopped. Cook, stirring occasionally, until the onion is soft and translucent, about 6–8 minutes. Season with a pinch of salt and a few grinds of pepper while it cooks.
   • Add the 600 g of coarsely chopped spinach to the pan. Cook, stirring, until the spinach wilts down and any excess moisture has mostly evaporated, about 3–5 minutes. Remove from heat and set aside to cool slightly.
2. Make the roux:
   • In a medium saucepan, melt 100 g butter over medium heat until fully liquid and foaming slightly.
   • Whisk in 100 g flour and cook the mixture, stirring constantly, for 1–2 minutes. This cooks out the raw flour taste and forms a smooth paste (the roux). Keep the heat moderate so it doesn’t color too much.
3. Turn the roux into a béchamel:
   • Gradually pour in the 1 l whole milk while whisking constantly to prevent lumps. Start with a small splash, whisk to combine, then continue adding the milk in steady streams until fully incorporated.
   • Bring the sauce to a gentle simmer, whisking frequently, and let it thicken to a creamy consistency—this usually takes 5–8 minutes. Adjust the heat as needed to maintain a simmer without boiling vigorously.
4. Finish the sauce with pesto and cheese:
   • Remove the béchamel from the heat. Whisk in 300 g basil pesto until the sauce is smooth and uniformly green. Taste and season with salt and pepper as needed.
   • Stir in 100 g parmesan so it melts into the sauce, creating a silky, slightly cheesy pesto béchamel.
5. Preheat the oven and prepare the baking dish:
   • Preheat your oven to 180°C (350°F).
   • Lightly grease the bottom and sides of your baking dish with a little olive oil so the lasagna sheets don’t stick.
6. Assemble the lasagna:
   • Spread a thin layer of the pesto béchamel on the bottom of the greased baking dish to prevent sticking and to start the first layer of flavor.
   • Place a layer of lasagna sheets from the packet over the sauce so they cover the bottom. If your sheets need to be softened, follow package instructions—many oven-ready sheets work without pre-boiling.
   • Spread roughly one-third of the pesto béchamel evenly over the lasagna sheets.
   • Evenly distribute about one-third of the cooked spinach and onion mixture over the sauce layer.
   • Repeat the layering process two more times: lasagna sheets, béchamel, then spinach-onion mixture, until you’ve used your ingredients and the dish is built up in approximately three layers. Finish with a top layer of lasagna sheets and the remaining pesto béchamel spread across the top.
7. Top and season:
   • Sprinkle extra parmesan over the top of the final béchamel layer for a golden, savory crust when baked.
   • Drizzle a little olive oil over the very top if you like extra browning and sheen.
   • Finish with a few cracks of fresh black pepper and a light pinch of salt if desired.
8. Bake:
   • Place the assembled lasagna in the preheated oven and bake for 30–40 minutes, or until the top is bubbling and the edges are lightly browned. If the top deepens in color too quickly, cover loosely with a sheet of foil for the remaining time.
   • For a crisper top, finish the lasagna under the broiler for 1–2 minutes—watch closely to avoid burning.
9. Rest and serve:
   • Remove the lasagna from the oven and let it rest for at least 10–15 minutes. Resting allows the layers to set so the slices hold together cleanly.
   • Cut into portions and serve warm with an extra sprinkle of parmesan and a drizzle of olive oil, if desired.

Make-ahead and storage tips

This Veggie Pesto & Spinach Lasagna is great for making ahead. Assemble the lasagna in your baking dish, cover tightly with foil, and refrigerate for up to 24 hours before baking. If you want to freeze it, assemble and freeze uncovered for a couple of hours to firm up, then wrap tightly in foil and freeze for up to 2–3 months. Thaw overnight in the refrigerator before baking, and allow a little extra baking time if starting from chilled.

Serving suggestions

• A crisp green salad with lemon vinaigrette cuts through the richness and adds freshness.
• Crusty bread or garlic bread on the side is always welcome for mopping up any leftover sauce.
• A light white wine or a medium-bodied red pairs nicely with the herbaceous pesto flavors.

Ingredient notes and swaps

• Lasagna sheets: Use oven-ready sheets for convenience. If using regular dried sheets that require boiling, follow package instructions before assembling.
• Basil pesto: Homemade or store-bought both work. Use a quality pesto with bright basil flavor for the best results.
• Parmesan: Freshly grated parmesan integrates best into the sauce and melts more smoothly. Reserve a little extra for sprinkling on top before baking.

Troubleshooting

• If your sauce is too thin after simmering, allow it to cook a few extra minutes to evaporate more liquid and thicken. If it becomes too thick, whisk in a splash of milk to loosen.
• If the lasagna seems dry after baking, serve with extra warmed pesto béchamel or a spoonful of reserved milk-sauced mixture to add moisture to individual slices.
• To prevent soggy edges, ensure your spinach is well-cooked and excess moisture is reduced before layering. Drain or press any watery spinach if necessary.

Final thoughts

This Veggie Pesto & Spinach Lasagna is a celebration of simple, fresh ingredients layered into something special. The basil pesto gives the dish a fragrant brightness that sets it apart from heavier tomato-based lasagnas, while the creamy béchamel and parmesan provide the cozy, indulgent mouthfeel we all crave. Whether you’re feeding a family, entertaining friends, or making dinner for yourself with leftovers in mind, this lasagna is an easy, elegant go-to.

Enjoy baking, and savor each herb-filled, cheesy bite of this Veggie Pesto & Spinach Lasagna.

Veggie Pesto & Spinach Lasagna

A creamy spinach and basil pesto lasagna layered with a smooth parmesan béchamel.

Print Recipe Pin Recipe

Prep Time 25 minutes mins

Cook Time 25 minutes mins

Total Time 50 minutes mins

Servings: 9 servings

Ingredients Equipment Method Notes

Ingredients

  

• 1 large onion finely chopped
• 600 g spinach coarsely chopped
• 100 g butter
• 100 g flour plain/all-purpose
• 1 l whole milk
• 300 g basil pesto
• 100 g Parmesan + extra for sprinkling
• 1 packet lasagna sheets
• salt to taste
• pepper to taste
• olive oil for sautéing

Equipment

• large frying pan
• Saucepan
• hand whisk
• Spatula
• 25x35 cm (10x14") baking pan
• measuring scales
• Oven

Method

 

1. Preheat the oven to 180°C (356°F) fan.
2. Heat a large frying pan over medium heat and add a drizzle of olive oil.
3. Add the finely chopped onion and sauté until soft, then add the coarsely chopped spinach and cook until the liquid has evaporated; set the mixture aside.
4. In a saucepan over medium heat melt the butter, then whisk in the flour and cook for 1–2 minutes to form a roux.
5. Gradually add the milk in batches, whisking constantly to prevent lumps, and cook until the sauce thickens to a cream consistency.
6. Stir the cooked spinach and onion into the béchamel, then add the basil pesto, grated Parmesan, salt and pepper; mix until uniform and set aside.
7. Spoon a little of the cheese cream onto the bottom of a 25×35 cm (10×14") baking pan to prevent sticking.
8. Lay 3 lasagna sheets over the cream, spread a layer of the spinach-pesto cream on top, and repeat layers (lasagna sheets then cream) until the sheets and cream are used up.
9. Sprinkle extra grated Parmesan over the top and bake in the preheated oven for 35–40 minutes until golden and bubbling.
10. Allow the lasagna to rest until slightly cooled, then cut into portions and serve.

Notes

• You can substitute a different pesto if preferred.
• Parmesan can be swapped for smoked cheese or gouda.
• Use a little olive oil to prevent onions sticking while sautéing.