Bring a large pot of water to a boil. Cook lasagna noodles until al dente, just tender. Don't overcook, because they will become a little more tender in the oven. Drain and rinse with cold water. When cool enough to handle, lay the noodles flat and remove any moisture.
Preheat oven to 350 degrees F. Cover the bottom of a 9x13 inch baking dish with 1 cup marinara sauce.
Pulse kale in food processor until finely chopped or finely chop by hand. Remove and finely chop the mushrooms.
In a large saucepan, drizzle olive oil over medium heat. Cook garlic until just fragrant, 30 seconds to 1 minute. Add kale and cook, stirring often, for about 5 minutes. Season with salt and pepper. Stir in the mushrooms and cook until softened, 5-6 minutes. Remove from heat to a medium bowl and let cool slightly.
Add ricotta, Parmesan, egg, salt, and pepper to the kale and mushrooms.
On work surface, lay out a cooked lasagna noodle. Spread out about 1/3 cup of the kale mixture across the noodle. Roll the noodle up and place seam side down on prepared baking dish. Repeat with noodles and filling.
Cover the rolls with remaining marinara sauce and Mozzarella cheese. Cover with foil and bake in preheated oven until sauce is bubbly and cheese is melted, about 40 minutes. Remove the foil and bake an additional 5 minutes.