Line a mini muffin pan with paper liners. Set aside.
In a medium microwave safe bowl, microwave the Nutella and coconut oil in 30 second intervals, mixing until smooth.
Divide the mixture evenly into the prepared muffin pan. Top each Nutella cup with once slice of banana. Transfer the pan to the freezer until the Nutella cups are hardened, around 1 hour.
Remove from the freezer and transfer to an airtight container. Store in the fridge or the freezer.