The nuts are fine to use raw. However, roasting the hazelnuts and almonds prior to baking will help improve their flavor. Roasting bring out additional sweetness and mellows bitterness. To roast the nuts, bake them on a rimmed sheet pan at 350 degrees Fahrenheit for 10-15 minutes, stirring the nuts every 5 minutes. Don't get distracted - stay nearby and keep a close eye on them. You don't want to burn expensive ingredients!