Preheat oven to 375 degrees F. Line 2 baking sheets with parchment paper.
Slice off top and bottom bits of eggplant and cut into 1/4-rounds. Arrange on baking sheet then brush both sides with olive oil. Sprinkle lightly with salt and pepper then roast in the oven for 20 minutes.
Bring quinoa and 1 3/4 cups water to a boil in a saucepan. Reduce heat and simmer, covered for 15 minutes. Turn off heat and let rest for 5 minutes. Transfer to a large bowl and add spinach. Blend together and let rest for an additional 10 minutes. Meanwhile, whisk eggs and add oregano, basil and parsley in a separate bowl. Add egg mixture to quinoa spinach mixture and blend well. In another bowl, blend 1/2 the mozzarella and 1/2 the Parmesan into the ricotta and set aside.
In a 13x9 glass baking pan, spread 1 cup of marinara sauce evenly on the bottom. Layer half the eggplant slices in the bottom of the pan (about 6 large pieces). Spread quinoa mixture evenly on top. Dollop ricotta mixture on top of the quinoa mixture so it is spaced evenly around the casserole. Add another layer of eggplant on top then add about 1 cup of red sauce and then cover with another layer of quinoa/spinach to use it all up and then another dollop of ricotta mixture to use it all up. Cover with remaining marinara sauce then remaining mozzarella and Parmesan. Cover with foil and bake for 25 minutes. Uncover and bake for an additional 20 minutes. Serve hot. Also makes great leftovers.