Preheat oven to 325°F. Line a large cookie sheet with parchment paper; set aside.
In a food processor combine hazelnuts and 1/4 cup powdered sugar. Cover and process until nuts are finely ground. In a small bowl stir together flour, cocoa powder, cinnamon, and cloves. Set aside.
In a medium mixing bowl beat butter and lemon peel with an electric mixer on medium to high speed for 30 seconds. Add nut mixture. Beat until combined, scraping sides of bowl occasionally. Beat in flour mixture until combined.
Shape dough into 1-inch balls. Place 2 inches apart on the prepared cookie sheet. Using your thumb, make an indentation in the center of each cookie.
Bake for 8 minutes. Fill cookie centers with jam. Bake for 6 to 8 minutes more or until bottoms are light golden. Transfer to a wire rack; cool. Sprinkle lightly with additional powdered sugar or drizzle with melted chocolate.
Place filled cookies in a single layer in an airtight container; cover. Store at room temperature for up to 3 days or freeze for up to 3 months.