In a saucepan over medium heat, combine sugar and corn syrup. Stir until dissolved and the mixture starts to bubble.
Remove from heat and quickly stir in peanut butter and vanilla extract until smooth.
Fold in Rice Krispies cereal and mix until fully coated.
Gently fold in chopped Reese’s peanut butter cups.
Scoop small portions onto parchment paper and shape into cookies.
Melt chocolate chips in the microwave in 30-second intervals, stirring between each.
Drizzle or dip cookies in melted chocolate and let them set before serving.