Preheat oven to 325°F. Line cookie sheets with parchment paper.
In medium bowl, combine flour, baking powder and 3/4 cup hazelnuts. In large bowl, beat eggs and sugar with electric mixer until very light (eggs will be nearly white). Stir in vanilla. Gently fold flour mixture into eggs. Spread dough into 2 long strips on prepared pan.
Bake 25-30 minutes or until firm and lightly browned. Remove to cooling grid; cool completely. Cut into 1 in. slices; place slices on cookie sheet, cut side up. Return to oven and bake 7-8 minutes. Turn and continue baking until dry about 7-8 minutes. Cool completely on cooling grid.
Melt Candy Melts following package instructions. Dip one end of cooled biscotti in melted candy. Place dipped cookies on parchment-lined cookie sheet; sprinkle with chopped hazelnuts. Refrigerate to set.