Heat olive oil in a pan, add minced garlic and sauté until fragrant.
Add the thawed and drained spinach to the pan, cook for 3-4 minutes. Season with salt and pepper.
In a mixing bowl, combine the spinach mixture with ricotta cheese.
In a baking dish, spread a thin layer of marinara sauce. Layer with noodles, spinach-ricotta mix, mozzarella, and parmesan. Repeat layers ending with cheese on top.
Cover with foil and bake for 45 minutes. Remove foil and bake 15 minutes more until bubbly and golden on top.
Let lasagna rest for 10 minutes before serving.
Notes
For a richer flavor, use fresh mozzarella and add a pinch of nutmeg to the ricotta mixture.