Vegetarian Polenta Lasagna
This post may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases. Please read my disclosure.My vegetarian polenta lasagna uses sliced tube polenta instead of noodles for a naturally gluten-free version that’s ready in 45 minutes. I layer it with sautéed zucchini, red peppers, spinach, marinara sauce, and Parmesan cheese for a hearty casserole that serves 8. It’s also super easy, and takes only 20 minutes of prep compared to traditional lasagna’s 90-minute timeline!
I started making this polenta lasagna on weeknights when I wanted the comfort of traditional lasagna without the time commitment. The first time I tried substituting polenta for noodles, I was skeptical that it would satisfy my family the way pasta does. But the polenta slices bake into tender layers that soak up the marinara sauce, and the texture holds up better than I expected when cutting and serving.
The technique that makes this work is using pre-cooked tube polenta from the grocery store. I slice the tubes lengthwise into thin rounds, layer them like I would pasta sheets, and bake everything together. The polenta firms up in the oven while absorbing flavor from the vegetables and sauce. My kids didn’t notice the swap from pasta until I mentioned it, and they asked for seconds anyway.
This recipe has stayed in my rotation because it solves two problems at once. It gives me a gluten-free option when I need one for guests or family members, and it cuts my lasagna prep time in half. I can have this assembled and in the oven in 20 minutes, which means dinner is on the table before 7pm even on busy weeknights. The leftovers last up to 4 days in the fridge and taste even better reheated.
👩🏽🍳 Why I Love This Recipe
This polenta lasagna works because the pre-cooked tube polenta eliminates the step of boiling noodles and waiting for them to cool. Slicing the polenta cuts out 15-20 minutes of cooking time compared to traditional lasagna, plus I don’t have to deal with hot, slippery noodles that stick together (which is my least favorite part of making lasagna!)
The vegetable mixture is where I build most of the flavor. I cook zucchini, red peppers, and onions until they start browning and caramelizing, which concentrates their sweetness. The Italian seasoning and garlic add aromatic depth, and the spinach wilts down to add nutrients without making the dish feel heavy. When I stir in the marinara sauce at the end, everything melds together into a thick, cohesive filling.
What keeps me coming back to this recipe is how forgiving it is. I can swap out vegetables based on what’s in my fridge without changing the core technique. The polenta layers are sturdy enough to hold up under the weight of vegetables and sauce, so the lasagna doesn’t fall apart when I serve it. At 215 calories per huge serving, it leaves room for garlic bread or a side salad without feeling like I’ve overeaten. The whole grains from the polenta and protein from the cheese make each serving more filling than pasta-based versions.
🥘 Ingredients
This recipe is packed with veggies, spices and a handful of other simple ingredients. This is what I use to make it:
Extra Virgin Olive Oil: I use olive oil to sauté the vegetables. It adds richness and helps the vegetables brown.
Red Onion: I love the color red onion brings, and it has a slightly sweeter, milder flavor than yellow onion, although yellow onion will work in this recipe too.
Red, Yellow, or Orange Bell Peppers: I use diced bell peppers for sweetness and color. Red, orange or yellow all work, I don’t recommend green because it has a more bitter flavor.
Garlic: I use fresh minced garlic cloves. Jarred garlic works in a pinch but doesn’t have the same flavor punch.
Zucchini: I seed and dice the zucchini so it cooks quickly, but doesn’t release too much water, and integrates into the sauce. Large chunks with seeds can get too watery when they cook down.
Spices: I use a combination of salt, pepper, crushed red pepper (for subtle heat), and dried Italian seasoning which brings a combination of herbs including basil, oregano, thyme and rosemary to this dish.
Baby Spinach: I use baby spinach because it’s pre-washed and tender. Regular spinach works if I remove the stems and chop it.
Spaghetti Sauce: I use jarred marinara sauce with no added sugar. I look for all-natural brands like Muir Glen or Cucina Antica. If I want a more spicy dish, I’ll choose an Arrabbiata sauce instead of regular marinara.
Prepared Organic Polenta: I use two 16-ounce tubes of pre-cooked polenta. I slice them lengthwise into thin rounds.
Shredded Parmesan Cheese: I use freshly shredded Parmesan for the best flavor and texture. Pre-shredded cheese has anti-caking agents.
Substitutions
Bell Peppers Substitute: I can use 3 cups diced mushrooms, eggplant (3 cups diced, seeded and pre-salted to release the water), or summer squash (3 cups diced) instead.
Baby Spinach Substitute: I can use kale (8-10 ounces, chopped with stems removed) or frozen spinach (10 ounces, thawed and squeezed dry).
Parmesan Cheese Substitute: I can use shredded mozzarella (1 1/2 cups), a shredded Italian cheese blend (1 1/2 cups), goat cheese (1 1/2 cups crumbled), or a dairy-free cheese alternative (1 1/2 cups).
🔪 How To Make
This recipe has a good number of steps, but I promise it’s still quite easy to make. Here’s how I make this vegetarian polenta lasagna:
Preheat and Prep: I preheat the oven to 450°F and coat a 9-by-13-inch baking dish with cooking spray. Then I heat olive oil in a large nonstick skillet over medium-high heat. I add the onion, peppers, zucchini, garlic, salt, pepper, Italian seasoning, and crushed red pepper. I cook, stirring occasionally, until the vegetables are tender and just beginning to brown, 4 to 6 minutes.
Add Spinach and Sauce: I add the baby spinach and cook until wilted, stirring once, about 3 minutes. Then I stir the marinara sauce into the vegetables and heat through, 1 to 2 minutes.
Slice Polenta: I slice the polenta tubes lengthwise into thin rounds. I recommend slicing as thin as you can without letting the rounds break (although if they do, that’s still ok since you can piece them back together in the baking dish!) I place half of the slices in a single layer in the prepared baking dish, trimming to fit if necessary.
Layer Cheese: I sprinkle 1/4 cup of the Parmesan over the polenta layer.
Add Vegetables: I top the cheese with half of the zucchini-spinach mixture and sprinkle with another 1/4 cup cheese.
Repeat Layers: I repeat the layering: one more layer of polenta, the remaining vegetables, and the remaining cheese on top.
Bake: I bake until bubbling and the cheese has just melted, 12 to 15 minutes.
Rest and Serve: I let the lasagna stand for about 5-10 minutes before cutting and serving, which helps it set.
💭 Expert Tips
My #1 Secret Tip for this recipe is to slice the polenta into thin, even rounds. If the slices are too thick, they won’t heat through properly and will have a dense, undercooked texture in the center. I aim for slices about 1/4 inch thick so they cook evenly in 12-15 minutes.
Other Tips To Keep In Mind:
- Brown the Vegetables: I cook the vegetables until they just start browning. This caramelization adds depth of flavor that makes the dish taste more like a restaurant version.
- Use No-Sugar-Added Sauce: I always check the label on marinara sauce to avoid added sugars. All-natural sauces let the vegetable flavors shine through.
- Drain Excess Liquid: I make sure to squeeze out any excess liquid from the spinach after it wilts. Too much liquid makes the lasagna watery.
- Assemble Ahead: I sometimes assemble this lasagna the day before, cover it, and refrigerate for up to 24 hours. I add 5 extra minutes to the baking time if baking from cold.
📖 Variations
This recipe adapts easily to different vegetables and flavors I have on hand. Here are some of my favorite ways to switch things up:
Add Mushrooms: I add 8 ounces finely diced mushrooms with the peppers and onions for an earthy, meaty texture.
Ricotta Version: I spread 1 cup ricotta cheese mixed with 1 egg and 1/2 teaspoon dried basil between the polenta and vegetable layers for extra creaminess. This also gives it more of a traditional lasagna feel.
Vegan Version: I use dairy-free cheese and skip the Parmesan, or use nutritional yeast (1/2 cup) mixed into the vegetable layer for cheesy flavor.
🍽 Serving Suggestions
I serve this polenta lasagna as a main dish with a simple green salad and my vegan garlic bread. It also pairs well with my vegan minestrone soup or these roasted green beans and potatoes as lighter side dishes. If I’m short on time I’ll just serve it on its own because it really is that satisfying!
🧊 Storage Directions
Storing: I slice and store the lasagna in an airtight container in the fridge for up to 4 days.
Freezing: I can freeze this lasagna for up to 3 months. I wrap it tightly in plastic wrap and then aluminum foil. I thaw it overnight in the fridge before reheating.
Reheating: I reheat individual portions in the microwave for 2-3 minutes, or in a 350°F oven for 15-20 minutes until heated through. I typically cover it with foil to prevent the cheese from browning too much.
❓ Recipe FAQs
Why is my polenta lasagna watery?
The vegetables release liquid as they cook. I make sure to cook them until they start slightly browning, which evaporates excess moisture. I also drain the spinach well after wilting, seed the zucchini, and avoid using too much marinara sauce (one jar is enough).
Can I use homemade polenta instead of tube polenta?
Yes, you can, but it will take a lot longer. First, you’ll have to make polenta from scratch and spread it 1/2 inch thick on a baking sheet. Then you’ll need to refrigerate it for at least 2 hours until firm, then cut it into shapes that fit your baking dish. This takes extra time but works the same as the tube polenta in this dish!
How do I keep the polenta from falling apart when slicing?
I recommend letting the lasagna rest for 5-15 minutes after baking so the layers set. I also use a sharp knife and wipe it clean between cuts to get neater slices.
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📋 Recipe Card
Vegetarian Polenta Lasagna
This vegetarian polenta lasagna uses sliced tube polenta instead of noodles for a naturally gluten-free version that's ready in 45 minutes. I layer it with sautéed zucchini, red peppers, spinach, marinara sauce, and Parmesan cheese for a hearty casserole that serves 8. It takes 20 minutes of prep compared to traditional lasagna's 90-minute timeline.
Servings: 8 servings
Calories: 215kcal
Ingredients
- 1 tbsp extra virgin olive oil
- 1 red onion
- 3 yellow/orange or red peppers diced
- 7 cloves garlic minced
- 4 zucchini finely diced
- ½ teaspoon salt
- ½ teaspoon freshly ground pepper
- ½ tbsp dried Italian seasoning or more to taste
- pinch crushed red pepper
- 8-10 ounces baby spinach chopped
- 1 jar of spaghetti sauce make sure to get one that’s all-natural, with no sugar added – I like Muir Glen Organic Garden Vegetable sauce
- 32 ounces prepared organic polenta (about two 16oz "rolls" of polenta) sliced lengthwise into thin slices
- 1½ cups shredded parmesan cheese divided
Instructions
- Preheat oven to 450 degree F. Coat a 9-by-13-inch baking dish with cooking spray. Heat oil in a large nonstick skillet over medium-high heat. Add onion, red pepper, zucchini, garlic, salt and pepper, Italian seasoning and crushed red pepper and cook, stirring occasionally, until the vegetables are tender and just beginning to brown, 4 to 6 minutes.
- Add spinach; cook until wilted, stirring once, about 3 minutes.
- Stir marinara sauce into the vegetables and heat through, 1 to 2 minutes.
- Slice polenta, and place polenta slices in a single layer in the prepared baking dish, trimming to fit if necessary.
- Sprinkle with 1/4 cup cheese, top with the zucchini/spinach mixture and sprinkle with 1/4 cup cheese. Then repeat: one more layer of polenta, one layer of veggies, and the remaining cheese on top.
- Bake until bubbling and the cheese has just melted, 12 to 15 minutes. Let stand for about 5 minutes before serving.
Notes
Expert Tips
- Use a pasta sauce that is all natural with no added sugar.
- You can use any kind of shredded cheese you like in this recipe. I opted for sharper parmesan, but mozzarella or goat cheese would taste fabulous as well!
- This is a great “clean out your fridge” recipe. If you don’t have the veggies I used, you can use just about any vegetable in this recipe and it will work great!
- If you need to make this ahead of time, assemble everything the day before and refrigerate — unbaked and covered — for up to 24 hours.
- Let stand for 15 minutes before cutting and serving.
Nutrition
Calories: 215kcal | Carbohydrates: 26.3g | Protein: 10.4g | Fat: 7g | Saturated Fat: 3g | Sodium: 880mg | Potassium: 547mg | Fiber: 5g | Sugar: 5g
Made this for dinner. It’s only my husband and me, so I cut it down and made in a 9X9 baking pan. However, the roll or polenta was barely enough for the smaller pan. I had to slice them super thin so there was enough. How did you make it work in a 9X13 pan? I also used less zucchini and added broccoli.
Delicious!!
Hi Bonnie! Thanks so much – I’m so glad you enjoyed this recipe and I love the addition of broccoli! Also, I didn’t realize this but the recipe had a typo! You actually need two rolls of polenta to fit in the 9×13 pan – I just updated the recipe card to indicate that! So next time, use two rolls of polenta and you should be all set! 🙂