In a large mixing bowl, combine the peanut butter and honey (or maple syrup). Stir well until smooth and well-blended.
Add in the rolled oats, chocolate chips, powdered sugar (if using), vanilla extract, and a pinch of salt. Mix until all ingredients are fully incorporated and a thick, sticky mixture forms.
Line an 8x8 inch square baking dish with parchment paper, allowing some overhang for easy removal later.
Transfer the mixture into the lined dish. Use a spatula or your hands to press it down firmly and evenly to create a smooth surface.
Place the dish in the refrigerator for at least 2 hours to set. If you're short on time, you can also place it in the freezer for about 30-45 minutes.
Once set, lift the mixture out of the dish using the parchment paper. Cut it into bars or squares as desired.
Store the bars in an airtight container in the fridge for up to 2 weeks.
Notes
Drizzle melted chocolate over the top before cutting for a professional touch.