Line your square pan with parchment paper, leaving a little overhang for easy removal.
In a mixing bowl, combine the creamy peanut butter, honey, and vanilla extract. Stir until the mixture is smooth, creamy, and slightly fluffy, with a pleasant peanut aroma filling the air.
Add the crushed graham cracker crumbs to the peanut butter mixture. Fold them in thoroughly until every crumb is coated and the mixture starts to come together into a sticky dough.
Press this dense, sticky mixture firmly into the prepared pan, using the back of a spoon or spatula to smooth the surface evenly. This helps create a compact base that holds together nicely once chilled.
Place the pan in the fridge and chill for about 30 minutes, allowing the mixture to firm up and relax, making it easier to cut later.
While the base chills, melt the chocolate chips in a microwave-safe bowl in 20-second bursts, stirring well after each, until smooth and glossy. Add a teaspoon of vegetable oil if you like a shinier finish.
Remove the pan from the fridge and pour the melted chocolate evenly over the firm peanut butter layer. Use a spatula to spread it out smoothly, ensuring full coverage with a glossy surface.
Refrigerate the assembled bars for at least 2 hours or until the chocolate is completely set and the bars are firm.
Once chilled, lift the bars out using the parchment overhang. Use a sharp knife or pizza cutter to cut into squares or rectangles, wiping the blade clean between cuts for neat edges.
Serve the bars immediately or store them in an airtight container in the fridge. They’re perfect straight from the fridge or at room temperature for a softer bite.