Grease and lightly flour an 8-inch fluted tube mold. Or, grease an 8x4x2-inch loaf pan; line pan with parchment paper; grease paper. Set aside.
Combine flour, baking powder, and baking soda; set aside. In a bowl beat butter with an electric mixer on medium speed for 30 seconds. Add the brown sugar; beat until mixture is combined. Add eggs, 1 at a time, beating on medium speed until combined (batter may appear curdled).
Combine orange peel, juice, corn syrup, and vanilla. Add flour mixture and juice mixture alternately to butter mixture, beating on low speed after each addition just until combined. combine fruits and nuts. Fold into batter. Spread into prepared pan.
Bake in a 300 degree F oven about 1 hour in tube pan, about 1-1/2 hours in loaf pan, or until a wooden toothpick comes out clean. If necessary, cover cake with foil the last 15 to 30 minutes to prevent overbrowning.
Cook cake in tube pan on wire rack 10 minutes. Remove from pan; cool thoroughly on rack. Or, thoroughly cool the cake in loaf pan on wire rack; remove from pan. Wrap cake in brandy- or juice- moistened 100-percent cotton cheesecloth. Overwrap in foil. Store in refrigerator 2 to 8 weeks; remoisten cheesecloth about once a week or as needed. If desired, sprinkle with pearl sugar and garnish with orange-peel curls before slicing. Makes 16 servings.