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Zucchini Lasagna

This Zucchini Lasagna is a comforting, hot, meaty, cheesy, saucy, low-carb, gluten free, keto take on your favorite Italian comfort food! It’s layered with thinly sliced zucchini, the BEST homemade Bolognese, creamy ricotta (with a secret no-grainy ricotta trick), nutty Parmesan and gooey mozzarella cheese. This veggie-loaded zucchini lasagna recipe is every bit as scrumptious as traditional lasagna and the most scrumptious way to use zucchini from your garden. Best of all, this zucchini lasagna is not watery! I’m sharing my fool-proof techniques to prevent watery zucchini lasagna, so you end up with perfect al dente zucchini noodles and rich sauce every time. This zucchini lasagna is guaranteed to be your new favorite make ahead, freezer-friendly, gluten-free comfort food!
Course Main Dish
Cuisine Italian
Prep Time 50 minutes
Cook Time 50 minutes
Total Time 1 hour 40 minutes
Servings 12 servings

Ingredients

Layers

  • 4 medium zucchini (7-8 oz. each) sliced 1/8" thick (approx 30 slices)
  • 3 cups freshly shredded mozzarella
  • 1/2 tablespoon kosher salt DON’T use table salt

Bolognese Sauce

  • 1 pound Hot Italian sausage bulk casings removed
  • 1/2 large yellow onion chopped
  • 1 carrot diced
  • 1 stalk celery diced
  • 1/4 teaspoon red pepper flakes
  • 3-4 cloves garlic minced
  • 1 28 oz. can crushed tomatoes
  • 1 cup water
  • 2 tablespoons tomato paste
  • 2 tablespoon chopped fresh basil or 2 tsp dried
  • 2 tablespoons chopped fresh parsley or 2 tsp dried
  • 1 1/2 teaspoons beef bouillon or better than bouililon
  • 1 1/2 teaspoons sugar more or less to taste
  • 1 teaspoon dried oregano
  • 1/2 teaspoon dried thyme
  • 1/4 tsp EACH salt, pepper
  • 1 whole bay leaf

Ricotta Filling

  • 1 egg
  • 15 oz. ricotta cheese
  • 3/4 cup sour cream full fat is best
  • 1/2 cup freshly grated Parmesan cheese
  • 1 1/2 tablespoon chopped fresh basil or 1 1/2 tsp dried
  • 1 1/2 tablespoon chopped fresh parsley or 1 1/2 tsp dried
  • 1/4 tsp EACH nutmeg, pepper

Instructions

Zucchini

  • Spread zucchini slices out in a single layer over several layers of paper towels. Sprinkle evenly with kosher salt and let rest at least 15 minutes while you begin the sauce and make the filling. After 15 minutes, brush the salt off with a wad of paper towels and pat dry.
  • Preheat oven to the broil setting. Top two baking sheets with baking racks (or work in batches) and spray racks with cooking spray. Evenly line the zucchini slices on the baking racks in a single layer; spray the tops of the zucchini lightly with cooking spray.
  • Broil one baking sheet at a time on the top rack (about 5-inches away from broiler) for 4-6 minutes, or until lightly brown, watching closely so the zucchini doesn't burn; repeat with the second tray. *If you don’t have baking racks, spray two baking sheets and broil; transfer zucchini slices to paper towels once broiled to absorb excess moisture.

Sauce

  • In a Dutch oven or large pot, brown sausage, onion, carrots and celery over medium heat. Add garlic and red pepper flakes and cook 30 more seconds. Drain grease.
  • Add all remaining Bolognese ingredients, cover, and bring to a boil. Remove lid and reduce heat to low. Simmer gently uncovered for 10 minutes, stirring occasionally. The sauce should be quite thick after simmering.

Filling

  • While sauce is simmering, preheat oven to 350 degrees F. Add all of the Ricotta Filling ingredients to a large bowl and mix until combined.

Assemble

  • To assemble, lightly grease a 9x13 pan. Spread a quarter of the Bolognese sauce on the bottom of the prepared pan (layer will be thin). Top with one third of the zucchini slices in an even layer, overlapping if needed. Spread one third of the ricotta filling over top in an even layer and evenly top with 3/4 cup mozzarella cheese.
  • Repeat layers (Bolognese, zucchini noodles, ricotta, mozzarella) two more times for a total of 3 complete layers. To finish, top with remaining Bolognese and remaining mozzarella.

Bake

  • Cover lasagna with foil and bake for 30 minutes. Uncover and bake an additional 20 minutes or until hot and bubbly. Remove from the oven and let stand 15 minutes before serving. Garnish with fresh parsley if desired.

Notes

Tips and Tricks

  • Turkey or lean ground beef substitute:  if you want to use lean ground beef or turkey, make sure to season with Italian seasonings, onion powder, garlic powder, paprika and fennel. Fennel is crucial for authentic Italian flavor.  
  • Cottage cheese substitute:  you can use all cottage cheese in place of the ricotta and sour cream but I suggest using 2 cups cottage cheese and 3/4 cups sour cream. I also suggest pureeing the cottage cheese for an even creamier texture.  
  • Use a mandoline to slice zucchini into even 1/8 thick noodles.  It is practically impossible to do by hand without harming yourself.
  • Thick Bolognese:  the Bolognese will be thick and a little hard to spread which is a good thing! The sauce will absorb water released from the zucchini when baked to become the perfect consistency.

MAKE AHEAD 

This zucchini lasagna is best served fresh but can be prepared in stages – prep the zucchini noodles, make the filling, make the Bolognese - so all that’s left to do is assemble.  If you assemble the zucchini lasagna entirely ahead of time, it will still be delicious, but a little more watery.
  • Prep zucchini noodles. Slice, salt and broil the zucchini noodles per recipe directions.  Line a baking sheet with paper towels followed by a single row of zucchini noodles. Top with parchment paper and repeat paper towels, zucchini noodles, parchment until all of the noodles are layered.  Cover tightly with plastic wrap and refrigerate.  Blot zucchini of any excess moisture before assembling the lasagna.
  • Make ricotta filling.  Whisk all of the filling ingredient together, cover and refrigerate until ready to use.
  • Make Bolognese. You can make the sauce up to 3 days in advance and refrigerate or freeze for up to 3 months.  If you use cold, thawed sauce in your lasagna, add an extra 10 minutes to the baking time with the foil on.
  • Assemble and Refrigerate. You can assemble the entire zucchini lasagna a day in advance and refrigerate (without baking).  The zucchini will continue to release water so I suggest removing water accumulated at the bottom of the dish with a turkey baster.  Let the lasagna sit on the counter for 15 minutes before baking then add an extra 10 minutes to the baking time with the foil on. If you bake ceramic or glass dishes straight from the refrigerator, they can shatter so don’t skip the counter time!

HOW TO STORE and Reheat

  • Storage:  Let lasagna cool to room temperature and cover tightly with foil. Refrigerate for up to 5 days or freeze for longer storage.
  • Whole pan of lasagna:  Let glass or ceramic dishes sit on the counter for 15 minutes while you preheat the oven to 350 degrees F.  Remove water accumulated at the bottom of the dish with a turkey baster. Bake, covered, for 30-35 minutes.
  • Single servings:  transfer a serving of lasagna to a microwave safe plate. Microwave for 90 seconds then at 20 intervals until warm through.

How to Freeze Zucchini Lasagna

Zucchini lasagna is best if frozen before baking for the best texture, that way you aren’t baking the zucchini noodles twice. It is also best to thaw frozen zucchini lasagna before baking so you can remove some of the excess moisture.

To freeze unbaked zucchini lasagna:

  • Assemble lasagna according to recipe directions in a freezer safe dish.
  • Cover baking dish all the way around with 2 layers of plastic wrap.
  • Cover the lasagna tightly with one layer of aluminum foil.
  • Label lasagna and freeze for up to 3 months.
  • When ready to bake, thaw lasagna in the refrigerator for 24 hours.
  • Transfer lasagna to the counter for 15 minutes while you preheat the oven to 350 degrees F.
  • Meanwhile, remove water accumulated at the bottom of the dish with a turkey baster.
  • Cover tightly with foil and bake for 30 minutes, uncover and bake an additional 20-30 minutes.

To freeze baked zucchini lasagna: 

There isn’t really a reason to freeze baked zucchini lasagna except if you have leftovers. In that case, it’s best to freeze individual servings:
  • Let lasagna cool completely.
  • Slice into individual servings.
  • Transfer slices to freezer safe airtight containers.
  • Label and freeze for up to 3 months.
  • To reheat, either thaw and microwave until warm OR
  • Transfer serving to a baking sheet and bake from frozen at 350 degrees F for 20-25 minutes.