Mix the sauce first by combining the oil, parmesan, seasonings, garlic and herbs.
Set each flank steak flat on a surface and coat one side with the seasoned garlic and cheese oil. Top with the crumbled pistachios and then a layer of spinach.
Roll the steaks from one end to the next and secure in place with a toothpick.
Bake at 375 degrees for 30 minutes. Remove and serve hot!
Recipe Notes
You can use some fresh basil leaves if you prefer!