Preheat your oven to 375°F and bring a small pot of water to a boil.
Cook the lasagna noodle according to package directions until al dente, then drain and set aside.
Heat olive oil in a skillet over medium heat, then add the minced garlic and ground beef, breaking it up with a spatula.
Season the beef with sea salt, black pepper, and dried oregano, cooking until browned and fully cooked through.
Stir the fresh baby spinach into the beef until just wilted, then remove the skillet from the heat.
In a small individual baking dish, spread a spoonful of marinara sauce on the bottom.
Cut the cooked lasagna noodle into three equal pieces to fit your dish.
Layer one piece of noodle, followed by half of the beef and spinach mixture, a dollop of ricotta, and more marinara.
Repeat the layer once more, finishing with the final noodle piece, the remaining marinara, and a sprinkle of mozzarella.
Bake for 15-20 minutes until the cheese is melted and the edges are bubbling and golden.