Heat oven to 325 degrees F. In large bowl, whisk together flour, baking powder and salt.
In second large bowl, beat together butter and sugar on medium-high speed until smooth and creamy, about 3 minutes. Add eggs and lemon rind; beat until fully incorporated. On low speed, add cherries and nuts. Gradually beat in flour mixture until fully incorporated and dough forms (dough will be stiff).
Shape dough into 2 flattened logs, 8 inches long and 3 inches wide. Place on ungreased baking sheet.
Bake in 325 degree F oven for 35 minutes. Transfer logs to wire rack; let cool 10 minutes. With serrated knife, cut logs into 1/2-inch-thick slices; place on baking sheet, cut side down. Bake in 325 degree F oven another 20 minutes. Transfer biscotti to wire rack; let cool completely.
In microwave-safe bowl, combine chocolate and shortening. Microwave on high power for 1 minute; stir to blend. Microwave at 30-second intervals, stirring to melt completely. Dip half of each biscotti into melted chocolate; sprinkle chocolate with ground nuts or red or green crystallized sugar, if desired. Place on waxed paper-lined baking sheets; let stand until chocolate is set. Store in airtight container at cool room temperature for up to 3 days. Makes 2 dozen.
