Transfer the peanut butter, pure maple syrup, and butter to a large thick-bottomed pot. I use my Dutch oven. Heat over medium heat, and stir constantly until all of the wet ingredients and melted together and well combined. Stir in the vanilla extract, crispy rice cereal and a pinch of sea salt. Gently mix until all of the rice krispy cereal is coated in the peanut butter mixture.

Lightly spray a 12-hole muffin tray with cooking spray. Transfer the rice crispy mixture to the muffin cups, filling them ⅔ of the way up and using the back of a spoon to press the mixture into an even layer in each hole. This recipe makes 15 cups, so you can either use a second muffin pan if you have one, or wait until the first batch is finished to make the final three rice crispy treats.

Transfer the chocolate chips and butter to a microwave-safe bowl and microwave for 30-second intervals, stirring well between each interval, until the mixture is completely melted (about 2 minutes total).

Spread a light layer of melted chocolate over the peanut butter layer of each rice crispy cup. Refrigerate for at least 2 hours or freeze for 30 minutes or until the chocolate has fully set up.

Run a butter knife between each treat and the edge of the muffin tin in order to release the treats. Pop them out of the tray, and enjoy!

Store peanut butter rice crispy treats in an airtight container or a large zip lock bag in the refrigerator for up to 10 days. Freeze for up to 3 months in a sealed container or freezer bag.

While the treats are stable at room temperature (up to 70 degrees Fahrenheit), they will become soft and eventually melt if they stay at a warm temperature for too long. Keep this in mind when planning for or transporting these chocolate peanut butter rice krispy cups.