Line your pan with parchment paper, leaving overhang on the sides for easy lifting.
In a large microwave-safe bowl, warm the peanut butter and honey together for about 30 seconds, then stir until the mixture is smooth and glossy, filling your kitchen with a nutty aroma.
Add the vanilla extract to the peanut butter mixture and stir well to combine.
Pour in the rolled oats and mini chocolate chips, then fold everything together with a spatula until evenly coated and sticky.
Transfer the thick mixture into your prepared pan and press it down firmly with a spatula, creating an even, compact layer that feels satisfying to the touch.
In a microwave-safe bowl, melt the chocolate chips in short bursts of about 30 seconds, stirring well after each until smooth and shiny, with the aroma of melting chocolate filling the air.
Pour the melted chocolate evenly over the pressed mixture in the pan, spreading it smoothly with a spatula for a glossy, chocolatey top.
Place the pan in the fridge and chill for at least 2 hours, or until the chocolate is set and the bars are firm to the touch.
Once chilled, lift the entire block out of the pan using the parchment overhang, then cut into 12 neat bars with a sharp, hot-dipped knife for clean edges.
Serve the bars straight from the fridge for a chewy, satisfying treat, and store any leftovers in an airtight container in the fridge for up to a week.