Preheat oven to 350ºF.

In a large bowl, mix together brown sugar, melted butter, corn syrup, and quick oats.

Press mixture firmly into a buttered 9×13 pan.

In a microwave-safe bowl, mix melted chocolate chips and peanut butter together in 30-second intervals (stirring between each interval) until fully melted.

Spread chocolate mixture on top of oat mixture.

Bake in preheated oven for 20-25 minutes.

Cool completely before cutting into bars (Once they are almost cool, I often stick them in the fridge for an hour or so to help them firm up faster).

Enjoy immediately or freeze for later.

Refrigerate leftovers.