Preheat the oven to 425 degrees Fahrenheit.
Heat a large skillet over medium heat and add oil. Once the oil is warmed, add the carrots, zucchini, onion, and salt & pepper. Cook about 5-8 minutes until veggies are softened.
While the veggies are sautéeing, cook lasagna according to package instructions if you aren’t using no-boil lasagna (drain and set aside).
Next add spinach in batches stirring frequently, until the spinach has wilted then remove it from heat.
Add veggies and ricotta into a food processor or blender and pulse until less chunky but not purèed. Make sure everything is combined.
To assemble the lasagna, spread ½ cup marinara sauce evenly on the bottom of your baking dish (my baking dish is approx. 8”x12”) then layer in the following order: one layer of lasagna noodles, then spread ⅓ of the ricotta veggie mixture evenly over the noodles, then top with 2 tbsp of the grated parmesan, ¼ cup of the shredded mozzarella and repeat 3 times. For the top layer, just add sauce and parmesan, and mozzarella cheese.
Bake, covered with aluminum foil for 15 minutes, then remove the foil and bake for another 10 minutes.
Let cool before serving.