Begin by mixing the creamy peanut butter, honey, and vanilla extract in a medium bowl until the mixture is smooth and fragrant, about 2 minutes. It should be thick but easy to stir, with a slightly sticky feel.
Add the graham cracker crumbs to the peanut butter mixture and fold everything together with a spatula until well combined. The mixture will become thick and crumbly but should hold together when pressed.
Line your 8-inch square pan with parchment paper, leaving some overhang for easy removal. Using the spatula, press the mixture evenly into the prepared pan, smoothing the top for a flat surface. Press firmly to compact the mixture and create an even layer.
Place the pan in the refrigerator for at least 2 hours, or until the mixture is firm and set. The bars will become chewy and fudgy as they chill.
Once firm, melt the chocolate chips in a microwave-safe bowl in 20-second bursts, stirring between each, until smooth and glossy. This will take about 1 minute total. The melted chocolate should be silky and shiny, ready to be poured.
Spread the melted chocolate evenly over the chilled peanut butter mixture using a spatula or the back of a spoon. Cover the entire surface with a smooth, glossy layer of chocolate.
Return the pan to the fridge for another 30 minutes, or until the chocolate is set and shiny. The bars will be firm, with a beautiful glossy top and a chewy base.
Using the overhang of parchment paper, lift the entire block of bars out of the pan and place on a cutting board. Slice into 12 even squares with a warm, sharp knife for clean, neat edges.
Serve the bars immediately or store them in an airtight container in the fridge. They keep well for up to a week and are perfect for a quick, indulgent treat.