Butter on Butter! No need to add an extra kick of butter to your microwave popcorn we did it for you! One step above the regular butter flavors Xtra butter will satisfy the creamy salty taste you crave. Sure to please family and friends for any snacking occasion. Gluten-Free ingredients non-GMO and whole-grain kernels make Xtra Butter the easy snacking choice. New Consumable Shelf-Stable Microwave Popcorn.