Preheat oven to 350 degrees Fahrenheit. Spread hazelnuts in an even layer on a baking sheet. Bake for 8-10 minutes until toasted. Remove from oven and allow to cool for 1-2 minutes.
Transfer hazelnuts to a clean kitchen towel. Using the towel, rub the hazelnuts together to remove as much of the skins as possible. Once complete, place hazelnuts in the bowl of a food processor.
Process hazelnuts, stopping occasionally to wipe down sides, until it goes from crumbly to a creamier consistency. Once hazelnuts start to turn into butter, add the remaining ingredients. Process until chocolate hazelnut butter is completely smooth.
Store chocolate hazelnut spread in an airtight jar in the refrigerator. The spread will thicken as it chills. Before using, stir to reintegrate. Chocolate hazelnut spread can be stored in the refrigerator for up to two weeks.
Notes
*Agave syrup can be used as a vegan alternative to maple syrup. If you are not concerned about making this vegan, honey also works well. Start with a little less of either than called for in the recipe and add more to taste. Adapted from my Homemade Honey Roasted Almond Butter.