If you have leftover Mini McGriddles Breakfast, it's best to store them in an airtight container or wrapped tightly in plastic to keep them fresh.  To reheat them, you can use a microwave or toaster oven: When reheating in the microwave, wrap the sandwich in a damp paper towel or place it on a microwave-safe plate and microwave for 15-20 seconds or until heated through. If you're using a toaster oven, wrap the sandwich in foil and heat for about 5-7 minutes or until warm. Reheating the breakfast sandwich can cause the pancake buns to lose their texture.