Preheat your oven to 375°F (190°C).
Bring a pot of water to a boil and cook the whole wheat lasagna noodles according to package directions until al dente, then drain and set aside.
In a medium skillet over medium-high heat, brown the ground beef until fully cooked, breaking it into small crumbles. Drain any excess fat.
Stir the marinara sauce into the cooked beef and simmer for 2 minutes to meld flavors.
In a small bowl, combine the ricotta cheese, beaten egg, dried oregano, garlic powder, sea salt, and black pepper.
In a small individual-sized baking dish, spread a thin layer of the meat sauce on the bottom.
Place half of a lasagna noodle over the sauce, followed by a layer of the ricotta mixture and a handful of fresh spinach.
Repeat the layers, ending with a final noodle sheet topped with the remaining meat sauce.
Sprinkle the shredded mozzarella and grated parmesan evenly over the top.
Cover with foil and bake for 20 minutes, then remove the foil and bake for an additional 10 minutes until the cheese is melted and slightly browned.
Let the lasagna rest for 5 minutes before serving to allow the layers to set.