Preheat your oven to 175°C (350°F) and line your 8-inch square pan with parchment paper, leaving some overhang to lift out the bars easily.
In a large mixing bowl, combine the peanut butter, honey, and melted butter. Use a spatula to stir everything together until the mixture is smooth and creamy, and you can see a glossy sheen forming.
Add the rolled oats, chocolate chips, and vanilla extract to the bowl. Gently fold everything together until the oats are evenly coated and the chocolate chips are distributed throughout the mixture. It will be thick and sticky.
Transfer the mixture into your prepared pan. Use the back of a spatula to press it down evenly across the surface, creating a compact layer. This helps the bars hold together after baking.
Bake in the preheated oven for about 15–18 minutes, or until the edges turn a golden brown and smell warm and toasty. You might hear a gentle bubbling around the chocolate chips.
Once baked, remove the pan from the oven and let it cool on a wire rack for about 10 minutes. The mixture will firm up slightly as it cools, making it easier to handle.
Using the overhang of parchment, lift the bars out of the pan and transfer them to the wire rack. Allow them to cool completely, about 20–30 minutes, until they feel firm to the touch.
Once cooled, cut the bars into squares with a serrated knife. For cleaner slices, dip the knife in hot water and wipe dry between cuts.
Enjoy these hearty, chewy bars as a satisfying snack or a quick energy boost. Store any leftovers in an airtight container at room temperature for up to 3 days, or freeze for longer storage.