Add the cocoa, sugar, vanilla, salt and oil to the food processor and continue to process until well blended, about 1 minute. The finished spread should have the consistency of creamy peanut butter; if it is too dry, add in a little extra hazelnut oil until the desired consistency is achieved. Remove to a container, cover and refrigerate until needed. Allow the spread to come to room temperature before using, as it thickens considerably when refrigerated.
Makes about 1 1/2 cup.