Preheat oven. Preheat oven to 180 C | 360 F and line a baking tray with baking paper.
Make base layer. Add the ingredients to a high speed blender or food processor and blend until it resembles fine crumbs and sticks together when pressed. Spoon mixture into a 24 mini muffin pan (see note below) and press down with the back of a teaspoon. Place it in the freezer.
Toast hazelnuts. Place the hazelnuts in a single layer on the baking tray and bake for about 5 to 8 minutes until the skins have darkened and are easy to remove.
Skin the hazelnuts. Rub the hazelnuts between your hands or in a tea towel to remove as much of the skins as possible. Don’t stress if you cant get all the skin off. This step can be skipped if you buy hazelnuts without the skin on.
Make nutella layer. Place the hazelnuts into a high-speed blender and process until they form a smooth paste. Add all the other ingredients and process until combined and smooth. Spoon the mixture evenly onto the bases and place back into the freezer for at least 30 minutes to set.
Make chocolate layer. Melt the coconut oil in saucepan on low heat. Once melted, remove from heat and add the sweetener. Whisk briskly until well combined. Then add the cacao powder, stirring until well mixed through. Spoon the chocolate on top of the nutella layer and place back into the freezer and let it set completely, approximately 2 hours.
Storing them. Thaw slightly before removing them from the mini muffin pan. Store in a airtight container in the freezer and remove a few minutes before serving.