Espresso-Toffee Chewy Crispy Bars make the transition from childhood treat to grown-up fare thanks to the addition of espresso powder to the dessert bars.
Melt butter over medium-low heat; stir in espresso powder. Add marshmallows, and stir until melted. Add toffee bits and cereal; toss well to combine. Press into a 13 x 9-inch pan coated with cooking spray.