Roasted Vegetable and Pesto Lasagna (The Cozy, Green, Cheesy One)

Roasted vegetables, basil pesto, ricotta, marinara, and mozzarella layered into a sliceable, weeknight-friendly vegetarian lasagna.

Prep Time 35

Cook Time 55

Total Time 1 30

Course Main Dish

Cuisine Italian-American

Servings 8

9 x 13-inch baking dish ceramic or metal works; if using a metal pan, check at the 45-minute mark because it can brown a touch faster
Rimmed baking sheet half-sheet pan is ideal for roasting the vegetables; use two smaller sheets if you need more space so the vegetables roast instead of steaming
Large Mixing Bowl for tossing vegetables with oil and seasoning; a stockpot can do the job if that is what you have
Medium bowl for mixing the ricotta filling; a large measuring jug also works
Foil to cover the lasagna for the first part of baking; parchment under foil helps prevent cheese sticking, but is optional
Microplane or fine grater for parmesan and lemon zest; substitute a box grater on the fine side
chef knife and cutting board a sharp knife matters here because you want clean veggie cuts for even roasting
Instant-read thermometer (optional) not required, but if you want certainty, the center should be around 165F to 175F when fully hot and set

1 large zucchini cut into 1/2-inch half-moons; substitute yellow squash
1 large red bell pepper cut into 1-inch strips; any color works, but red is sweetest
1 red onion cut into 1-inch wedges; keep the root end intact so it does not fall apart
8 ounce cremini mushroom halved if large; leave whole if small; oyster mushroom also works
2 tablespoon olive oil extra virgin; substitute avocado oil
1 teaspoon kosher salt use 3/4 teaspoon if using fine salt
1/2 teaspoon black pepper freshly ground if possible
1 teaspoon dried oregano or Italian seasoning

15 ounce ricotta whole milk makes the richest filling; part-skim works but can bake up slightly drier
1 egg helps the ricotta set for cleaner slices; for egg-free, omit and add 2 tablespoon grated parmesan
1 cup parmesan finely grated; pecorino romano is a salty, sharper option
2 cup baby spinach chopped; thawed frozen spinach also works, but squeeze it very dry first
1 teaspoon lemon zest optional, but it brightens the pesto and roasted vegetables
1 clove garlic finely grated or minced; optional if your pesto is already garlicky
1/2 teaspoon kosher salt adjust depending on how salty your pesto and marinara are

3 cup marinara sauce store-bought is fine; choose one you would happily eat with a spoon
1/2 cup basil pesto store-bought or homemade; if very thick, loosen with 1 tablespoon warm water or olive oil
2 tablespoon water to thin the marinara slightly if using no-boil noodles; skip if using cooked noodles and a loose sauce

12 lasagna noodle use no-boil for fastest assembly or use traditional noodles cooked to very al dente
12 ounce mozzarella shredded low-moisture melts best; fresh mozzarella can be used but blot well to avoid watering out the lasagna
1 tablespoon olive oil for greasing the pan; butter also works
2 tablespoon parmesan for the top; optional but gives a crisp, savory finish
2 tablespoon basil thinly sliced for serving; optional

Heat the oven to 425F. Lightly grease a 9 x 13-inch baking dish with 1 tablespoon olive oil and set it aside. If you are using traditional lasagna noodles (not no-boil), bring a large pot of well-salted water to a boil now so it is ready when you are.
Cut the vegetables into chunky, roast-friendly pieces (not tiny dice). The goal is caramelization, not collapse. Add zucchini, bell pepper, red onion, and mushroom to a large bowl.

Add 2 tablespoons olive oil, 1 teaspoon kosher salt, 1/2 teaspoon black pepper, and 1 teaspoon dried oregano to the vegetables. Toss until everything is glossy and evenly seasoned.
Spread the vegetables onto a rimmed baking sheet in a single layer with a little breathing room. Roast for 25 minutes. Stir once at the halfway point so you get browning on multiple sides.
When done, the edges should look deeply browned in spots, mushrooms should be smaller and juicy, and onions should be sweet and slightly blistered. Set aside to cool for a few minutes. If you see liquid pooling on the pan, do not panic; just avoid dumping that liquid into the lasagna (it can make the bottom watery).

In a medium bowl, mix ricotta, egg, 1 cup parmesan, chopped spinach, lemon zest, garlic, and 1/2 teaspoon kosher salt until combined. The mixture should be thick and spoonable. If it seems wet (some ricotta brands are looser), stir in an extra 2 tablespoons parmesan.
Taste a tiny dab. You are looking for a lightly salty, bright base because the pesto and marinara bring their own punch. Adjust salt only if it tastes flat.

In a small bowl, stir the pesto so it is spreadable. If it is very stiff, loosen it with a splash of warm water or olive oil (1 tablespoon is usually enough).
If using no-boil noodles, stir 2 tablespoons water into the marinara. No-boil noodles need a little extra moisture to hydrate, and this small adjustment helps the lasagna bake up tender instead of chewy.

Spoon about 3/4 cup marinara into the bottom of the prepared baking dish and spread it thinly. This keeps the first noodle layer from sticking and starts the saucy foundation.
Add a layer of lasagna noodles (about 4 noodles, depending on your brand and pan). Break noodles as needed to fit; tight seams are fine.
Spread half of the ricotta mixture over the noodles. A small offset spatula helps, but the back of a spoon also works. Then scatter on half of the roasted vegetables, keeping them in an even layer.
Dollop about 1/4 cup pesto across the vegetables and lightly smear it around. You want pockets of pesto flavor, not a perfectly uniform green layer. Sprinkle on about 1/3 of the mozzarella.
Spoon about 1 cup marinara over the top and spread gently.
Repeat with noodles, remaining ricotta mixture, remaining roasted vegetables, another 1/4 cup pesto, another 1/3 of the mozzarella, and about 1 cup marinara.
Finish with a final layer of noodles, the remaining marinara, and the remaining mozzarella. Sprinkle 2 tablespoons parmesan over the top for a browned, savory crust.

Cover the dish tightly with foil. Bake at 375F for 30 minutes. Keep it covered so the noodles soften and the center heats through before the top over-browns.
Uncover and bake for 20 minutes. The sauce should be bubbling at the edges and the top should be melted with golden spots.
Let the lasagna rest on a cooling rack for 15 minutes before slicing. This is the difference between a scoop and a slice. If you want extra clean pieces, rest 25 minutes (it will still be hot).
Slice and serve. Top with basil if you like. If you want to lean into the idea of the best veg lasagna recipe for weeknights, serve it with a big salad and call it done.