Prepare baking dish: Line an 8x8 square baking dish with parchment paper.
Melt chocolate and peanut butter: Place 1 ½ cups chocolate chips, and ⅓ cup peanut butter in a medium sized, microwave-safe bowl. Melt in the microwave in 30-second intervals, stirring between each interval.
Add rice krispies: When chocolate is smooth and melted, add 1 cup rice krispies and stir well.
Spread in pan: Spread into prepared pan, dust with flaked sea salt (if desired.)
Freeze: Freeze for 15 minutes. Cut into 8 bars.
