Begin preheating the oven to 325° F (160° C). Melt the butter in a medium bowl and line a cookie sheet with a silicone mat or parchment paper.
Place the graham crackers in a bag or bowl and crush them to the desired consistency. Try to create different sized pieces for a varied streusel.
Add the crushed graham crackers into the melted butter and pour the sugar in. Mix the contents until consistently distributed.
Dump the graham cracker mix out onto the lined cookie sheet and spread evenly, breaking up clumps.
Bake for about 18 minutes. Halfway through, stir the crackers, rotate the pan, and continue baking until a deep golden color and the scent of toasted graham fills the air.