Mix flour, baking powder and salt until well blended; set aside. Beat sugar and margarine in large bowl with electric mixer on medium speed until light and fluffy.
Add eggs, bananas and vanilla; beat until well blended. Gradually add flour mixture, mixing until well blended after each addition. Stir in crushed cereal.
Divide dough in half with floured hands; place on lightly floured surface.
Roll each half into 14x2-inch log.
Place, 2 inches apart, on nonstick baking sheet.
Bake 25 to 30 min. or until lightly browned.
Remove from baking sheet to wire rack; cool 5 min.
Transfer to cutting board. Use serrated knife to diagonally cut each log into 12 slices.
Place, cut-sides up and 1/2 inch apart, on same baking sheet.
Bake an additional 12 to 15 min. or until slightly dry.
Remove to wire racks; cool completely. Melt chocolate as directed on package; drizzle over biscotti.
Let stand until chocolate is firm. Store in tightly covered container at room temperature.