Preheat your oven to 375°F (190°C).
Cook the lasagna noodles according to package instructions, then drain and set aside.
In a mixing bowl, combine the drained spinach, ricotta cheese, half of the mozzarella cheese, half of the Parmesan cheese, minced garlic, oregano, basil, salt, and pepper. Mix well.
Spread a thin layer of marinara sauce on the bottom of a 9×13-inch baking dish.
Place 3 lasagna noodles on top of the sauce.
Spread half of the spinach and cheese mixture over the noodles, then top with more marinara sauce.
Repeat the layering process with 3 more lasagna noodles, the remaining spinach and cheese mixture, and more marinara sauce.
Top with the remaining 3 lasagna noodles, marinara sauce, and the remaining mozzarella and Parmesan cheeses.
Cover the baking dish with foil and bake in the preheated oven for 30 minutes.
Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden.
Let the lasagna cool for a few minutes before serving. Enjoy!