Line 8-inch (20 cm) square baking pan with enough parchment paper to overhang edges; set aside.
In saucepan set over medium-low heat, combine peanut butter, white chocolate chips, maple syrup and coconut oil. Cook, stirring constantly, for 2 to 3 minutes or just until melted and runny. Remove from heat; stir in cereal until well coated.
Scrape into prepared pan; press firmly to even thickness. Refrigerate for about 1 hour or until set and firm.
Remove from pan; cut into bars.
Drizzle with melted dark chocolate and sprinkle with additional Cocoa PEBBLES™ Cereal if desired.