Caramelized Onion Lasagna

Caramelized Onion Lasagna

22 Reviews
From the EatingWell Kitchen

This unusual lasagna with portobello mushrooms, sweet onions, spinach and Gorgonzola cheese has a rich, complex flavor. It's also great with goat cheese instead of Gorgonzola, if you prefer.

Ingredients 9 servings

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Original recipe yields 9 servings
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  • 8 ounces lasagna noodles, preferably whole-wheat
  • Caramelized Onion Filling
  • 3 tablespoons extra-virgin olive oil
  • 3 large sweet onions, thinly sliced (about 10 cups; see Kitchen Tip)
  • 4 medium portobello mushroom caps, gills removed (see Kitchen Tip), diced
  • 1/2 cup red wine
  • 1 teaspoon salt
  • Freshly ground pepper, to taste
  • Spinach & Cheese Filling
  • 4 cups baby spinach
  • 2 cups nonfat ricotta cheese
  • 1/2 cup chopped fresh basil
  • 1/2 teaspoon salt
  • White Sauce & Topping
  • 2 tablespoons extra-virgin olive oil
  • 3 tablespoons all-purpose flour
  • 2 cups low-fat milk
  • 1/2 teaspoon salt
  • 2 ounces crumbled Gorgonzola cheese
  • 1/3 cup chopped walnuts
  • 1/4 cup chopped fresh basil


  • Active

  • Ready In

  1. Bring a large pot of water to a boil. Cook noodles until not quite al dente, about 2 minutes less than the package directions. Drain; return the noodles to the pot and cover with cool water.
  2. To prepare onion filling: Meanwhile, heat 3 tablespoons oil in a large skillet over medium heat. Add onions and cook, stirring frequently, until golden brown and very soft, about 25 minutes. (If they begin to stick, add water 1/4 cup at a time to release them and prevent burning.) Add mushrooms and cook, stirring, until just beginning to soften, about 3 minutes. Add wine and 1 teaspoon salt and continue cooking until most of the liquid is absorbed, 2 to 3 minutes. Remove from heat; stir in pepper.
  3. To prepare spinach filling: Place spinach, ricotta, basil and 1/2 teaspoon salt in a food processor and process until smooth.
  4. To prepare white sauce: Heat 2 tablespoons oil in a medium saucepan over medium-high heat. Add flour and stir until bubbling, about 30 seconds. Gradually whisk in milk and 1/2 teaspoon salt and bring to a boil, whisking constantly. Cook, whisking, until the sauce has the consistency of thick gravy, about 1 minute. Add Gorgonzola and gently whisk until it is melted. Remove from the heat. (The sauce will continue to thicken as it sits.)
  5. To assemble lasagna: Preheat oven to 375 °F. Coat a 9-by-13-inch baking pan with cooking spray.
  6. Drain the noodles and spread out on a kitchen towel. Spread 1/2 cup white sauce in the prepared pan. Place a layer of noodles over the sauce. Spread half of the spinach filling over the noodles and top with one-third of the onion filling. Evenly spread 1/2 cup white sauce over the onions. Repeat with another layer of noodles, the remaining spinach filling, half the remaining onion filling and half the remaining white sauce. To finish, top with a third layer of noodles, spread the remaining onion filling over the noodles and then spread or dollop the remaining white sauce on top. Sprinkle with walnuts and basil.
  7. Bake until hot and bubbling, about 30 minutes. Let rest for 5 minutes before serving.
  • Make Ahead Tip: Cover and refrigerate the caramelized onion filling (Step 2) for up to 1 day.
  • Kitchen Tip: Onions contain a volatile compound called lachrymator that reacts with the fluid in your eyes and makes them water. To chop them without crying, try wearing goggles, burning a candle nearby or cutting them under cold water. To mellow the bite of a raw onion, soak it for an hour in 1 cup cold water, 1/4 cup vinegar and 1/2 teaspoon salt and then rinse thoroughly.
  • Kitchen Tip: The dark gills found on the underside of a portobello mushroom cap are edible, but can turn a dish an unappealing gray/black color. Remove the gills with a spoon, if desired.

Nutrition information

  • Serving size: 1 piece
  • Per serving: 387 calories; 18 g fat(6 g sat); 6 g fiber; 41 g carbohydrates; 16 g protein; 98 mcg folate; 25 mg cholesterol; 12 g sugars; 0 g added sugars; 1650 IU vitamin A; 9 mg vitamin C; 318 mg calcium; 2 mg iron; 706 mg sodium; 614 mg potassium
  • Carbohydrate Servings: 2
  • Exchanges: 2 1/2 starch, 2 vegetable, 1 medium fat meat, 2 fat

Reviews 22

February 20, 2016
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By: EatingWell User
Good meatless alternative We used regular lasagna noodles instead of whole wheat. We skipped all of the added salt, which was two teaspoons. That's a lot of salt. We used one package of thawed frozen chopped spinach instead of leaf spinach. We used crumbled blue cheese instead of Gorgonzola. Yes, Gorgonzola is a blue cheese. If you're not a fan of blue cheeses, you'll want to use a different cheese in the white sauce. I did remove the gills from the mushrooms, but I think it was probably unnecessary in this recipe since the mushrooms are added to caramelized onion with red wine. It all turns sort of purple anyway. The lasagna holds together very well even though it doesn't have the usual layers of heavy sauce and mozzarella. In using frozen chopped spinach as we did, I pulsed the spinach in the food processor before adding the ricotta. The mixture was just right that way. Pros: Vegetarian dish that holds together well Cons: Lots of steps
August 27, 2013
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By: chandvakil
Yum I thought this was pretty good, however, I am not really a fan of blue cheese so I should have used goat cheese or mozzarella. But, it still was pretty tasty. My mom, a fan of blue cheese, loved it! So, if you like blue cheese, use it - if you don't maybe sub with a different cheese. Pros: Healthy, filling Cons: Takes a long time to make, requires lots of ingredients
April 25, 2013
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By: EatingWell User
Awful! I followed this recipe to the letter, and I know how to cook. My caramelized onions were superb. My mushrooms sauteed with red wine were perfect. I hand-picked the basil, which was fragrant and wonderful. But when you put spinach and ricotta in a food processor, you get an unappetizing green goo. Putting walnuts on top does not help. This recipe wasted my time -- and worse -- my cheese. Me and mine love creative vegetarian dishes, but this is a vegetarian adaptation gone awry.
March 11, 2013
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By: Jilary
I thought this lasagna was amazing! I made it with goat cheese instead of gorgonzola as I don't care for blue cheese. I did accidentally use honey goat, but that didn't seem to negatively alter the flavor. I also added 3 cloves of garlic to the white sauce and added a small amount of parmigiano reggiano on top of the second layer of ricotta and another sprinkle on top of the final white sauce layer, maybe 1/4 of a cup total. I don't think it really added anything, so I likely won't use it next time. I used organic whole wheat no boil noodles, and was a little worried since I don't normally like whole wheat noodles, but I didn't even notice them in this recipe! As far as lasagnas go, this one is pretty simple, especially if you make the onions and ricotta mix a day ahead like I did. I assembled the lasagna early in the day and let it sit in the refrigerator for a few hours just to be sure the noodles would absorb enough liquid to cook properly in 30 minutes. Pictures don't do this justice either, the ricotta layer is a beautiful bright green from the spinach and basil, and the onions and mushrooms are a lovely shade of purple. The only thing I'd change is to put the walnuts and chopped basil under the final white sauce layer, because the basil kind of dried out, and the walnuts might be nice if they absorb some of the sauce! If you don't want to buy a bottle of red wine for this, I would think vermouth would work well too, but you won't get the pretty purple color. I used a
September 27, 2012
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By: EatingWell User
Nice lasagna, but lacks pizzazz This is a nice lasagna, though the taste was a little too mild. I will probably make it again at some point, but will add garlic and additional spices, including white pepper, dried basil, and oregano. Pros: Healthy! Lots of veggies Cons: Somewhat bland tast
August 29, 2012
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By: EatingWell User
My Husband's new favorite dish :) I would also have added an extra onion because I ran out of the onion layer. Wish I would've read the comments before cooking it! Pros: It tastes AMAZING especially since it doesn't contain meat. Cons: It takes a while to prepare...but completely worth it!
February 08, 2012
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By: EatingWell User
Sooooo good! This is a great recipe for veggie night because it has robust flavors. If you have left overs it also does really well as a side dish to a simple meat dish (grilled pork chops or baked chicken for example) as it has both carbohydrates and vegetables. It keeps well in the fridge for at least 2 days after baking (that's how long it took our 2 person household to eat the entire thing). It does take a while to prepare, but that is the nature of lasagne. Pros: lots of veggies without the boring veggie taste
December 03, 2011
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By: EatingWell User
De-Lish! I used goat cheese in place of the gorgonzola, and added the (suggested) extra onion, which I cooked for much longer than 25 minutes for a more complex sweetness. I didn't have fresh basil, so I used fresh parsley and dried basil. Skipped the walnuts and basil topping. It was perfect! I thought the amount of sauce was spot-on, and that all of the veggies combined for a perfect taste. Will definitely make again!!!
June 05, 2011
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By: EatingWell User
THE BEST vegetarian recipe I have EVER tasted! My friend made this last night and told me where to find it when I begged her for the recipe. As I understand it, she doubled the sauce and used white no boil noodles. Other than that, she's a pretty good rule follower. The complexity of flavors was amazing. It did not taste oniony or mushroomy or spinachy. It was just a wonderful combination of flavors and textures. I can't wait to try making it myself-I'll just allow lots of time to create wonderfulness! Pros: Couldn't stop eating it Cons: It's a big deal to make