In a medium bowl, mix together the basil, ricotta, eggs, garlic powder, salt, and pepper until smooth.
Spread ¼ cup of marinara sauce on the bottom of your slow cooker to prevent sticking.
Start layering with uncooked lasagna noodles, breaking them as needed to fit.
Add a third of the ricotta mixture, spreading it into a thin layer.
Top with a third of the mushrooms, zucchini, yellow squash, and chopped spinach. Sprinkle with a third of the grated mozzarella.
Drizzle with another ¼ of marinara sauce.
Repeat these layers two more times, ending with a layer of noodles and the remaining marinara sauce.
Top with fresh mozzarella slices.
Place a clean kitchen towel under the lid to catch steam. Cook on HIGH for 3 hours, or until noodles are tender and the sauce is absorbed.
Garnish with fresh basil and Parmesan cheese before serving. Enjoy!
