Prep the pan: Line an 8x8-inch baking pan with parchment, leaving overhang on two sides. This makes it simple to lift out the slab later.

Make the base: In a bowl, stir together melted butter, 1 cup peanut butter, vanilla, and a pinch of salt until smooth.

Add the dry ingredients: Mix in graham cracker crumbs until evenly moistened. Add 1 3/4 cups powdered sugar and stir until a thick, dough-like mixture forms. If it’s sticky, add the remaining 1/4 cup sugar.

Press into the pan: Transfer the mixture to the lined pan. Press it down firmly and evenly using the back of a spoon or a flat-bottomed measuring cup. A tight pack helps the bars slice cleanly.

Make the chocolate topping: In a microwave-safe bowl, combine chocolate chips and 1/4 cup peanut butter. Microwave in 20–30 second bursts, stirring after each, until smooth and glossy. Or melt gently over a double boiler.

Top and smooth: Pour the melted chocolate over the peanut butter base. Tilt the pan and use a spatula to spread it into an even layer.

Optional garnish: Sprinkle flaky sea salt over the chocolate while it’s still warm for a craveable sweet-salty finish.

Chill: Refrigerate for 1–2 hours, or until the chocolate is set and the base is firm.

Slice and serve: Lift the slab out using the parchment. Warm a knife under hot water, dry it, and cut into 16 squares (or smaller bites). Clean the knife between cuts for neat edges.