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Polenta Lasagna with Roasted Red Pepper Sauce - an easy, vegan adaptable main dish that is perfect for the holiday table. Gluten-free! #veganthanksgiving #polentalasagna #veganlasagna #vegetarianmaindish #veganchristmas #polenta #lasagnarecipes #glutenfreelasagna

Polenta Lasagna

5 Stars 4 Stars 3 Stars 2 Stars 1 Star 4.7 from 29 reviews
  • Author: Sylvia Fountaine | Feasting at home
  • Prep Time: 45
  • Cook Time: 45
  • Total Time: 1 hour 30 minutes
  • Yield: 8 1x
  • Category: main, vegetarain, vegan adaptable
  • Method: baked
  • Cuisine: italian
  • Diet: Vegetarian


This Polenta Lasagna is made with layers of firm polenta, a savory spinach mushroom filling, melty cheese, and a roasted red pepper sauce.  If making polenta from scratch, allow 8 hours for refrigeration. Vegetarian and gluten-free. Vegan-adaptable.


  • 2 x 18-ounce tubes of polenta (store-bought). OR See notes for making your own!
  • 6 ounces  Ricotta cheese ( or sub this vegan tofu ricotta ) about 1-1 1/2 cups.
  • 12 cups grated mozzarella cheese (or use smoked mozzarella for great flavor, jack, or use melty vegan cheese)
  • Generous pinch salt, pepper and nutmeg

Spinach Mushroom Filling:

  • 2 tablespoons olive oil
  • one onion, diced
  • 46 garlic cloves, rough chopped
  • 1016 ounces mushrooms (sliced)
  • ½ teaspoon salt
  • 1/2 teaspoon pepper
  • 1 teaspoon Italian seasoning ( or use 1 tablespoon fresh rosemary or thyme)
  • 2 heaping handfuls baby spinach, chopped ( or 8 ounces frozen)

Smoky Red Pepper Sauce ( or use 2 cups store-bought marinara)

  • 1 roasted red pepper (out of a jar is OK) about 1/2 cup – 3/4 cup total
  • 1 x 14 ounce can of diced tomatoes and their juices
  • 2 tablespoons olive oil
  • 1 teaspoon smoked paprika
  • 1 teaspoon cumin
  • 1 teaspoon Italian seasoning
  • 1/2 teaspoon salt and pepper
  • 1 teaspoon sugar

Quick Pesto drizzle (or use store-bought pesto)

  • 1 cup packed basil ( or Italian parsley)
  • 12 teaspoons lemon zest
  • ½ cup olive oil
  • 1 fat garlic clove
  • salt and pepper to taste

Homemade Firm Polenta  (requires 8 hours of refrigeration time)


  1. If making with homemade Polenta- make this first and let cool 8 hours in the fridge to set up. ( You could make this ahead, along with the sauce, filling and pesto drizzle.)
  2. Preheat oven to 400F (prep and assembly will take around 45 minutes- with store-bought polenta)
  3. Make filling: Heat 1-2 tablespoon olive oil in a large skillet over medium-high heat. Saute the onion, stirring until tender, about 5 minutes, add garlic and cook 2 more minutes.  Turn skillet to medium ( or medium-low)  and add the mushrooms and add salt pepper and Italian seasoning, and saute until the mushrooms release their liquid and this evaporates, about 10 minutes. Add the chopped spinach and wilt and mix to combine, adding a splash of water if needed. Cook-off any liquid. Adjust salt to your taste.
  4. While the filling is cooking, make the Red Pepper sauce:  Add the diced tomatoes (and juices) to the blender and add the drained roasted pepper. Add 2 tablespoons olive oil, salt, pepper, smoked paprika, cumin and Italian herbs. Blend until creamy and smooth. If the sauce is too thick to get motor running, add a little water (a tablespoon at a time) just to get it going. Taste. It should have a sweet smoky flavor.
  5. Prep the two tubes of polenta if using store-bought. (Remember to taste it)  It’s easiest to cut the tube in half. Then in quarters, so each quarter yields 3 equal slices. So 12 slices each from each tube about 3/4 inch thick.
  6. Assemble: Spray a 9×13 inch baking dish with olive oil. Place 1/2-2/3  cup sauce on the bottom, coating bottom evenly. Add the first layer of polenta ( There are 2 layers). Top with all the filling, spreading it out evenly. Dot with spoonfuls of ricotta. Sprinkle lightly with salt, pepper and nutmeg. Top with shredded cheese. Pour 1/2-¾  cup sauce lightly over the cheese. Then, top with a final layer of polenta. Pour sauce over top (you may not need all) and using a spatula , evenly coat the polenta evenly. Save the remaining sauce for touching up after your remove the foil.  You could do this all ahead and refrigerate for 24 hours.
  7. At this point, you could add more cheese to the top, or keep it a little leaner, up to you. Cover tightly with parchment and foil and bake 20 minutes. Remove parchment/foil and bake uncovered for 15-20 more minutes until bubbling and warmed through. If you want it “saucy”, add more sauce.
  8. While it’s baking make the Pesto Drizzle. To make the pesto drizzle, simply place ingredients in a food processor and pulse until combined.
  9. When the polenta lasagna is finished cooking you could drizzle it lightly with the pesto or serve it on the side.


Keep in mind, not all store-bought polenta tastes the same. The Trader Joe’s brand is very flavorful. Your best bet is to cut a tiny piece off the end and taste it. If it tastes bland, you will need to bump up the flavor and salt in the filling and sauce. Things like garlic powder, onion powder and herbs help, and most importantly salt. The pesto drizzle will help a lot too.

To make your own firm polenta:

  1. Bring 8 cups water to a boil in a medium pot. Add 2 teaspoons salt, 2 teaspoons garlic powder ( or onion powder) and 1 Tablespoon fresh chopped herbs (rosemary, thyme, or sage) Or sub 1 teaspoon dried rosemary, thyme, Italian herbs or herbs de Provence. When water is boiling, very slowly pour and whisk in 2 cups cornmeal, whisking out any clumps.
  2. Cover, turn heat to low and cook 2o minutes, stirring once at 10 minutes.
  3. Grease an edged  sheet pan with olive oil really well. Grease a flat metal spatula really well. Pour out the polenta so it’s ¾ thick – noting, you will not need to use the whole sheet pan, so start on one end, spreading it out the the sides. See photos.
  4. If the polenta sticks to the spatula, just pour a little olive oil over the polenta, coating the spatula with it. Flatten it out to an even thickness. I usually cover about half of a large sheet pan  (leaving half of the sheet pan bare- because if you stretch it to fill the whole pan, polenta will be too thin).
  5. Let cool, then refrigerate until very firm, about 6-8 hours, or overnight (or up to 3 days).
  6. Cut into 16,  4-inch squares. (If you end up with some smaller scraps, I usually just tuck these in the lasagna in the first, base layer, underneath so they don’t show, leaving the prettier cuts for the top layer.)


  • Serving Size: 1 ½ pieces - With the basil pesto
  • Calories: 424
  • Sugar: 6.5 g
  • Sodium: 470.2 mg
  • Fat: 26 g
  • Saturated Fat: 7.8 g
  • Carbohydrates: 36.7 g
  • Fiber: 5.6 g
  • Protein: 13.8 g
  • Cholesterol: 32.5 mg