Line your baking pan with parchment paper and set it aside. Melt the butter in a saucepan over low heat until just fragrant and smooth, about 2 minutes.
Add the creamy peanut butter to the melted butter and stir until the mixture is glossy and well combined, about 1-2 minutes. The aroma should be warm and nutty.
Pour in the honey or corn syrup and stir until fully incorporated, resulting in a sticky, smooth mixture.
Remove the saucepan from heat. Fold in the rolled oats and vanilla extract, mixing thoroughly until the oats are evenly coated and the mixture is thick and sticky.
Transfer the mixture into the prepared pan. Use a spatula to press it firmly into an even layer, ensuring it's densely packed and smooth on top.
Sprinkle the chocolate chips evenly over the warm mixture, pressing them gently into the surface to help them melt slightly and stick.
Allow the bars to cool at room temperature for about 30 minutes, then transfer the pan to the fridge and chill for at least 2 hours until they are firm and set.
Once chilled, lift the bars out of the pan using the parchment paper overhang. Use a sharp knife to slice into neat squares, wiping the blade between cuts for clean edges.
Serve immediately or store in an airtight container in the refrigerator for up to a week. For softer bites, let the bars sit at room temperature for 10 minutes before enjoying.
