This vegetable crockpot lasagna recipe is perfect for lazy summer days. Layered with tender zucchini slices, sweet summer squash, and nutrient-rich spinach, it’s a simple and lighter version of classic lasagna.
Once the layers are assembled, the heat and moisture of the slow cooker create a mouthwatering casserole, softening the pasta, tenderizing the veggies, and melting the cheeses.
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This easy plant-based dinner is perfect for summer when zucchini and squash are in season. This convenient and inexpensive slow cooker vegetarian recipe is one to save and savor!
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Ingredients
- Zucchini or summer squash, or a combination
- Lasagna noodles, regular, not no-boil
- Tomato pasta sauce, such as marinara
- Canned tomatoes, petite-diced or crushed
- Red pepper flakes (optional) or use black pepper
- Low-fat cottage cheese, or part-skim ricotta
- Egg
- Garlic powder
- Basil, dried
- Oregano, dried
- Baby spinach
- Mozzarella cheese, part-skim, shredded
- Parmesan cheese, grated
- Italian parsley, chopped (optional)
Zucchini, summer squash: I like to use one of each because the colors look nice together, plus the squash adds sweetness. However, it’s fine to just use one or the other.
Lasagna noodles: Regular durum semolina wheat noodles, not oven-ready, hold up best in the moist environment of the slow cooker. No-boil noodles tend to become mushy, but if that’s all you keep handy, go ahead and use them.
Pasta sauce: Use your favorite. Marinara, garlic, Italian herbs—even a sauce with mushrooms is fine.
🍅Canned tomatoes: Small is the name of the game. If you have whole tomatoes or large pieces, toss them into the food processor or blend but don’t puree. Some texture is appealing.
Cottage cheese: I prefer low-fat to save on saturated fat, especially since this dish has plenty of cheese. If you like ricotta better, it is a fine substitute.
🥚Egg: You can omit the egg, but it helps the casserole hold together and adds protein and nutrients. You can swap in egg substitute, but do not use a flax egg!
🧄Garlic powder and dried herbs: These are fast and easy. Use fresh garlic if you want a bolder taste, but don’t put fresh herbs in the lasagna, except for a final sprinkle of chopped parsley.
Baby spinach: Recipes like this are what those cellophane boxes in the produce aisle are for. Ditto for baby kale or any other “power greens.” They are interchangeable in this lasagna.
Mozzarella: I used packaged, shredded low-fat mozzarella. You can also use whole milk cheese, but avoid fat-free, which has unfortunate taste and texture.
🧀Parmesan cheese: The important word is “grated.” Shredded Parmesan cheese will not melt the same way and truly has less flavor for lasagna. However, avoid the green cans of grated Parm, which contain wood pulp (cellulose powder).
How to make it
Whew! That’s quite a few ingredients, and building the layers in the liner of your Crockpot or (affiliate link) slow cooker is the most time-consuming part of the recipe.
That said, you are not going to get your stovetop dirty, just a knife, measuring cups or bowls and a (affiliate link) cutting board. (BTW: These eco-friendly cutting boards are durable, dishwasher safe, and maintenance-free—just the best!)
Before you assemble the layers, here are the preparatory steps:
Slice the zucchini and/or squash into smallish pieces. Cut the veggies in half lengthwise. Then, flat side down on the cutting board, cut in half again before slicing the quarters thinly. Done with chopping!
Next, combine the pasta sauce and canned tomatoes in a measuring cup or bowl and, if you want to liven it up, add some red pepper flakes or black pepper.
Mix the egg into the cottage cheese.
Finally, stir the garlic powder and dried herbs into the cottage cheese-egg mixture.
Now you are ready to build!
Layering the Lasagna (the fun part)
Coat the inside of Crockpot/slow cooker liner with non-stick cooking spray (olive oil spray is good for this recipe).
Pour ½ to ¾ cup of the tomato saucy mixture into the empty liner, just enough to thinly cover.
Place three lasagna noodles over the sauce, breaking as necessary, to fit the shape of the liner.
Spoon a thinnish layer of sauce on top of the noodles. Next add half the cottage cheese-egg mixture.
Top this with half the zucchini-squash pieces and 1½ cups of baby spinach leaves. Sprinkle a third of the mozzarella cheese over this bottom layer.
Build a second layer in the same fashion, starting with noodles, then sauce, remaining cottage cheese-egg, remaining veggie pieces and spinach leaves, and finally, a third of the mozzarella.
For the top layer, begin as usual with noodles, and use up the last spoonfuls of sauce. Top with the remaining mozzarella and grated Parmesan cheese.
Place the lid over the lasagna and set the time. The top should look cheese-glazed with ruffly noodle edges poking up when it has finished cooking.
Check for doneness by inserting a long, thin object into the lasagna to see if the noodles are soft. As the lasagna cools, the layers will hold together instead of falling apart easily. Allow up to 30 minutes of standing time.
Give the lasagna a generous sprinkle of chopped, flat-leaf parsley for an extra flavor boost before serving!
Storage
This vegetarian lasagna will keep in the fridge for three to five days. Freeze for up to three months.
To freeze a whole lasagna, you’ll need to place the liner in the freezer after it cools. Leave it there at least overnight. Once the lasagna is solidly frozen, slide it out of the liner and cover it with a double layer of (affiliate link) heavy-duty aluminum foil.
Return to frozen storage until you are ready to serve it. Reheat in a 350°F oven for an hour.
I usually freeze one to two pieces at a time. (A single frozen piece is a fantastic work lunch you can pop in the microwave and elicit envy from co-workers!) Two frozen pieces are a nice, quick weeknight dinner for two people.
How to serve
You need very little on the side to make this a meal. Two options are a simple green salad or orange wedges. Bread or breadsticks are also nice.
If you’re serving this to guests and want to include a dessert, something chocolatey contrasts well. In the summer, gelato or another frozen dessert is very refreshing and light.
This recipe is super easy for entertaining!
Is this recipe healthy?
With all the dairy and cheese in this recipe, you might wonder if you are doing your health a favor with this slow cooker recipe?
The answer is a resounding YES!
💪🏽Muscles: Each serving has 23 grams of protein from plant and dairy sources. It’s also rich in iron.
💖Heart-healthy: Despite the generous amount of cheese, it’s low in fat, especially saturated.
🦴Bones: It’s an excellent source of calcium, with more than 350 grams in each piece.
😌Gut: For a pasta dish, this offers a surprising amount of fiber in each serving.
🩸Diabetes-friendly: A single piece only has about two and a half servings of carbohydrates (36 grams), so it won't send blood sugar into orbit. The fiber helps, too, with glycemic control.
Micronutrition
It serves up plenty of vitamins, antioxidants, and minerals.
In addition to iron and calcium, you’ll get phosphorus, potassium, and some magnesium. The cooked tomato products are rich in vitamin C and lycopene, an antioxidant that may reduce the risk of some cancers.
⚠️Sodium, however, is high. Cheeses and canned tomato products have high amounts of salt. Look for no-salt canned tomato products and lower-sodium pasta sauce.
FAQ
Regular noodles will have the best texture. No-boil lasagna noodles become mushy in crockpots/slow cookers. That said, you can use them if you don’t have regular noodles handy.
Not the vegetables in this recipe. Sometimes, I add mushrooms. Because these have so much moisture, it's best to sauté or perhaps microwave them before adding.
Also, if you increase the amount of vegetables, you may need to cook them first.
Of course! Onions, fennel, baby kale, beet greens, bell peppers–all are wonderful choices. Stay away from firm, root veggies like potatoes, beets, and carrots, although you could use carrots if you grated them first.
A 5- to 6-quart Crockpot or slow cooker.
It’s fine to use gluten-free noodles, and you could try cheese made from plant-based milks. However, the texture may not be exactly the same. Nutritional yeast adds a Parmesan-like flavor when mixed into layers.
Yes. The layers can be assembled up to a day ahead of time in the liner. Put the lid on and store in the fridge. Let it sit for half an hour at room temperature before cooking. It may take longer to cook through.
Other recipes you might like…
If you love healthy pasta recipes, give this coconut curry pasta a go. It’s a one-pot meal made with tofu or chicken. The flavor is delicious, and it does not need any side dish!
Want another Italian one-pot special? My Chicken Leek Risotto recipe has a delightful creamy texture and is gluten-free. The recipe is easily made dairy-free, too!
If these savory flavors are your fav, try my easy sheet-pan Parmesan Garlic Chicken Thighs for weeknight bliss!
Slow Cooker Lasagna
Equipment
- 2 Bowls, medium
- spoons and cups, measuring
- 2 stirring spatulas or spoons
Ingredients
- 2 zucchini or summer squash, or a combination
- 9 lasagna noodles, regular not oven ready
- 24 ounces pasta sauce, 1 jar
- 14 ounces tomatoes, 1 can of petite diced or crushed
- ¼ teaspoon red pepper flakes, optional, or use black pepper
- 16 ounces low-fat cottage cheese, or part-skim ricotta
- 1 egg
- ½ teaspoon garlic powder
- ½ teaspoon basil, dried
- ½ teaspoon oregano, dried
- 3 cups baby spinach
- 2 cups part-skim mozzarella cheese, shredded, 1 package
- ¼ cup Parmesan cheese, grated, plus extra for serving
- ¼ cup Italian parsley, chopped, (optional)
Instructions
Prep for layers
- Wash hands thoroughly before starting. Lather with soap and rinse with running water.
- Cut the washed and trimmed zucchini and/or squash in half. Cut each half lengthwise. Place the flat side down on the cutting board and make another lengthwise cut, quartering the veggies. Slice thinly.
- In a medium bowl, combine the jar of pasta sauce and the canned tomatoes. Add red pepper, if using, or black pepper and stir.
- In another medium bowl, mix together the cottage cheese, egg, garlic powder, and dried herbs.
Assembling the Layers
- Coat the inside of a slow cooker (crockpot) liner with extra-virgin olive oil non-stick spray.
- Pour ½ to ¾ cup of the tomato sauce mixture into the slow cooker and spread so that it lightly coats the bottom. Top with three lasagna noodles, breaking as necessary to fit.
- Top the noodles with enough tomato sauce to cover them.
- Spread half the cottage cheese mixture over the first layer of noodles and sauce.
- Sprinkle half of the sliced squash and zucchini pieces over the cottage cheese. Dust the veggies with half of the fresh spinach. Use ⅓ of the package of shredded mozzarella over the spinach.
- Make the middle layer in the same fashion: Noodles (break to fit), tomato sauce, remaining cottage cheese mixture, remaining sliced veggies and spinach, ⅓ package mozzarella cheese.
- Make the final layer by starting with noodles and then sauce. Top this with the remaining mozzarella and grated Parmesan cheese. Put the lid on and cook on low for 3 to 4 hours or high for 1½ to 2½ hours.
- When the lasagna is finished cooking, shower with chopped Italian parsley and let stand for about 20 minutes to firm up.Cut into slices and serve, passing Parmesan and red pepper flakes on the side.
Notes
Nutrition
Copyright © 2025 Jani H. Leuschel
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