If using raw hazelnuts: Bake raw skin on nuts at 350 degrees for roughly 5 minutes or until medium golden in color. Put hazelnuts in clean dish towel and rub loose skins off.
Place the nuts into a food processor and grind. Warm nuts will blend into a butter faster. In beginning stages of grinding hazelnuts, they will resemble coarse sand, but as grinding continues, it will turn to nut butter.
Once the hazelnuts just start to become nut butter, add the oil one teaspoon at a time while grinding. You may only want to add 2 tsp oil and wait till after the rest of the ingredients are added to see if more oil is necessary.
At this point, add the rest of the ingredients and continue to blend until smooth.
You can adjust how much oil you add depending on your desired consistency of the chocolate hazelnut spread.
Spread can be stored for several months in the refrigerator.