Check the video below for easy visual instructions. I recommend using a kitchen scale for this recipe. Line a 6×6 inch (ca. 15 cm) pan or 7×7 inch (ca. 18 cm) pan with parchment paper. You can also use an 8×8 inch (ca. 20 cm) pan, however, the bars will be less thick. Add liquid sweetener, 1/2 cup peanut butter, vanilla extract, and salt to a bowl, and stir to combine.
Add the rice puffs to the bowl and stir until the rice cereal is well-coated. Depending on the size of the rice puffs, you will need 2 1/2 to 3 cups.
Spread the mixture in the pan and press it down as firmly as possible with a spatula. You can also use the bottom of a jar to compress the mixture.
I added 1/3 cup peanut butter in addition on top, but this step is optional!
Melt the chocolate chips in a double-boiler or in a microwave and pour the melted chocolate over the peanut butter cereal mixture. Spread it evenly.
Put the pan in the fridge for about 60 minutes (or in the freezer for a shorter time).
Cut into bars (which works best with a hot knife) and enjoy! Store leftovers in an airtight container in the fridge.