Add baby spinach, garlic powder, salt, ground black pepper, and olive oil to a bowl. Heat in the microwave for two minutes. Remove and stir. Add ricotta and whisked eggs to spinach mixture.
In a bowl, mix marinara with dried basil and dried oregano. Pour half of the marinara into the bottom of a 22 x 22 centimeter casserole dish.
Transfer ricotta-spinach mixture into a resealable plastic bag, seal the bag, then cut off one of the bottom corners of the bag. Cut the lasagna sheets across the middle into four equal pieces. Lay the pieces so one of the long edges is parallel with the edge of the work surface. Using the bag like you would a piping bag for icing, squeeze filling out lengthwise along the edge of the pasta that is closest to you, then roll up to secure filling. Once all cannelloni are stuffed and rolled, place them flat in the casserole dish, seam side down, over marinara sauce.
Pour the remaining marinara on top of the noodles and top with mozzarella and Parmesan. Bake for 20-25 minutes, or until heated through and cheese is bubbling.