Preheat your oven to 375°F (190°C).
In a skillet over medium heat, brown the ground beef until fully cooked, then drain any excess fat.
Using a vegetable peeler, slice the zucchini into long, thin ribbons to create a vegetable layer.
In a small mixing bowl, combine the ricotta cheese, egg white, chopped fresh spinach, oregano, garlic powder, sea salt, and black pepper.
Spread a small amount of marinara sauce on the bottom of a small oven-safe baking dish.
Layer the lasagna noodle (broken to fit the dish), half of the cooked beef, half of the zucchini ribbons, and half of the ricotta mixture.
Add another layer of marinara sauce, then repeat the layers with the remaining beef, zucchini, and ricotta.
Top with the remaining marinara sauce and sprinkle the shredded mozzarella cheese evenly over the top.
Cover the dish with foil and bake for 20 minutes.
Remove the foil and bake for an additional 10 minutes until the cheese is melted and the edges are bubbling.