Preheat the oven to 375 degrees
In a large skillet over medium heat, add the oil. When it starts to simmer, add the garlic and cook until it begins to brown, approximately one miinute.
Add the chopped spinach to the pan with garlic and stir until it begins to wilt, about 3-4 minutes. Remove from heat and let cool.
In a mixing bowl, combine the spinach, ricotta, mozzarella, parmesan cheese, egg, onion powder, italian seasoning, salt, pepper and stir until evenilymixed.
Pour one cup of pasta sauce into the bottom of a 9x13 baking dish.
Stuff each shell with a generous amount of the spinach and cheese mixture, and arrange in the baking dish.
Top with remaining marinara sauce and cover with aluminum foil, bake for 25 minutes.
Remove the foil and continue baking until the top begins to brown, another 10-15 minutes.
Top with remaining parmesan cheese and fresh basil.
