Line a 8"x 8" inch square pan with parchment paper and keep it aside.
In a large saucepan, add butter, peanut butter, and maple syrup. Cook the mixture on medium heat until the butter is melted and bubbles appear.
Remove the saucepan from heat and add the rice krispies. Mix until the rice krispies are fully coated with the peanut butter mixture.
Pour the mixture into the baking pan and spread it with a rubber spatula and press it down firmly. Place the pan in the freezer for 20 minutes until the bars are set.
In a microwave-safe bowl, add the chocolate chips and butter. Melt in the microwave in 30-second increments until the chocolate is melted. Mix until you get a smooth chocolate mixture.
Pour the chocolate ganache over the cooled bars and spread it evenly. Tap the pan lightly on the counter to smooth the top. Keep the pan in the freezer for 10 minutes until the chocolate layer is set.
Once fully set, lift the bars out using the parchment paper and place them on a cutting board. Cut into 16 pieces.
Notes
Store them in the fridge for 7 days. Freeze them for up to a month. Make sure to separate layers with parchment paper to prevent sticking, and let them thaw at room temperature before serving.