Preheat your oven to 350°F (175°C).
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large mixing bowl, cream together butter, brown sugar, and granulated sugar until light and fluffy.
Add eggs one at a time, mixing well after each addition. Stir in vanilla extract.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Fold in butterscotch chips, crushed graham crackers, and chopped nuts if using.
Pour the batter into a prepared baking pan and spread evenly. Bake for 30-35 minutes or until a toothpick comes out clean.
Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack.
Drizzle with butterscotch sauce and sprinkle with additional crushed graham crackers and nuts before serving.