Preheat your oven to 375°F and bring a pot of salted water to a boil.
Cook the whole wheat lasagna noodles until al dente according to package directions, then drain and set aside.
In a skillet over medium heat, add the olive oil and brown the turkey sausage until fully cooked, breaking it into small crumbles.
Stir in the minced garlic and baby spinach, sautéing for 1-2 minutes until the spinach is wilted and fragrant.
In a small bowl, whisk together the ricotta cheese, half an egg, dried oregano, sea salt, and black pepper until smooth.
Spread a thin layer of marinara sauce in the bottom of a small individual-sized baking dish.
Layer half a noodle (cut to fit the dish), half the ricotta mixture, half the sausage and spinach mixture, and a spoonful of marinara.
Repeat the layers with the remaining noodles, ricotta, and sausage, finishing with the remaining marinara and a topping of shredded mozzarella.
Cover the dish with foil and bake for 20 minutes, then remove the foil and bake for an additional 5-10 minutes until the cheese is melted and bubbly.