Preheat oven to 350 degrees.
Spray a mini muffin pan with cooking spray.
In a large bowl, using an electric mixer, blend the butter, sugar and brown sugar until creamy and fluffy.
Add the egg and vanilla extract. Mix well.
In a medium bowl, whisk graham crumbs, flour, baking powder and salt. Add to butter mix and stir until blended.
Using a 2 tablespoon measure, scoop dough into each muffin tin to the top and press down with your fingers so it's even.
Bake for 8-10 minutes.
Remove the pan from the oven and, while still hot and soft, press the back of your tablespoon measure into the dough of each cup to create a pit for the peanut butter to sit in.
Drop a teaspoon of peanut butter into the depression and place a marshamallow piece on top.
Sprinkle tops of marshmallows with dark chocolate shavings and return the muffin sheet to the oven for about 4 minutes, or until the marshmallows brown and the chocolate melts.
Remove from the oven and allow the smore's to cool in the pan for about 10 minutes and then enjoy.