Preheat oven to 375°F (190°C).
In a non-stick skillet over medium heat, brown the ground beef until fully cooked.
Season the beef with garlic powder, dried oregano, sea salt, and black pepper.
Add the fresh spinach to the skillet and stir until just wilted, then remove from heat.
Cook the lasagna noodle in boiling water until al dente, drain, and cut into three equal pieces.
In a small individual-sized baking dish, spread 2 tablespoons of marinara sauce on the bottom.
Layer one piece of noodle, a portion of the beef and spinach mixture, a tablespoon of ricotta, and more marinara.
Repeat the layers, finishing with the final noodle piece, remaining marinara, and the shredded mozzarella cheese.
Bake for 15 minutes until the cheese is melted and the edges are golden brown.