Line a mini muffin pan with paper liners. Set aside.
Place all of the ingredients in a microwave safe medium bowl. Heat in the microwave for 30 seconds and mix until smooth. If not fully melted, repeat the process until a smooth consistency forms.
Divide evenly in the paper liners, and transfer to the freezer until hardened. Place in an airtight container, and store in the fridge or freezer.
Notes
Do not store at room temperature. These Nutella cups will melt and not hold their shape. They are best stored in the fridge or freezer. I prefer mine in the freezer since I like them to be very hard.
Use a cookie scoop to distribute the Nutella mixture evenly. It helps avoid mess and gets the most Nutella mixture into the muffin pan. I use this cookie scoop.
Always use paper liners or a mini silicone muffin pan. The Nutella cups will stick to a regular mini muffin tin if you don't use paper liners.
Do not use any other oil in place of the coconut oil. Because coconut oil hardens when cold, it helps the Nutella cups hold their shape.