
Preheat the oven to 350° Fahrenheit. Line baking sheet with parchment paper.
Spread hazelnuts in a single layer on baking sheet and toast in the oven about 12 minutes, until they've browned a little and the skins are popping off in places. Remove baking sheet from oven and let cool slightly.
Remove skins from hazelnuts, either by pinching them between your fingers or by wrapping hazelnuts in kitchen towel completely and rubbing to remove papers.
In wide, medium bowl, microwave chocolate and coconut oil for 60 seconds, then stir. Microwave another 30 seconds, then stir. Continue process with 30-second bursts, stirring well in between, until chocolate is completely melted. See Notes for help with melting the chocolate. Alternately, you can melt chocolate and coconut oil together over double boiler.
Add peeled hazelnuts to high-speed blender and process until finely ground. Pour in melted chocolate and pulse until combined. Add in maple syrup, vanilla extract, and salt, and process until smooth.
Pour in 2 tablespoons non-dairy milk, and blend well. Continue adding milk in 2-tablespoon increments as needed until desired consistency is reached. I typically use 4-6 tablespoons. Transfer mixture to airtight container with lid and refrigerate until ready to use.