Preheat oven to 350°F (175°C). Line an 8 x 8-inch pan with nonstick foil, leaving an overhang on two sides to lift the bars out later.

If your butter is not already melted, melt 8 tablespoons (1 stick) butter in a microwave-safe bowl or small saucepan.

In a medium bowl, combine the melted butter, 1/2 cup sugar, and 1 1/2 cups graham cracker crumbs. Stir until the crumbs are evenly moistened and the mixture holds together when pressed.

Press the mixture firmly and evenly into the bottom of the prepared pan, using the bottom of a measuring cup or a flat spatula to compact it.

Bake for 9 minutes, then remove the pan from the oven and let the crust cool completely in the pan on a wire rack.

For firmer bars and easier slicing, chill the cooled crust in the refrigerator for at least 30 minutes.

Use the foil overhang to lift the crust from the pan, place on a cutting board, and cut into 16 squares. Store the bars in an airtight container in the refrigerator.