Preheat the oven to 400F. Coat a 9x13 baking dish with cooking spray.
Cook the frozen spinach according to the package instructions.
Combine cooked spinach, ricotta, parmesan, olive oil, egg, garlic powder, and a healthy pinch of salt and pepper in a small bowl then mix until well combined and smooth.
Combine pumpkin puree, milk, cinnamon, nutmeg, ginger, allspice, a healthy pinch of salt and pepper to another bowl then mix until well combined and smooth.
Spread out about a 1/4 of the pumpkin mixture on the bottom of the prepared baking dish. Top with lasagna noodles, 1/3 of the spinach ricotta mixture, another 1/4 of the pumpkin mixture, then 1/3 of the shredded mozzarella. Repeat this process until ingredients are gone, ending with a layer of mozzarella.
Cover the baking dish with foil then bake for about 30 minutes. Remove the foil then bake for another 10-15 minutes or until the cheese is golden and melty and sauces are bubbling.