Preheat the oven to 400ºF / 200ºC degrees. Line a 15 x 10 inch baking pan with foil, leaving an overhang on all sides. Spray the foil lightly with non stick cooking spray.
Cover the foil completely with graham crackers, breaking them as needed to fill any gaps.
Add the butter and brown sugar to a saucepan. Bring to a gentle boil without stirring until the butter has fully melted and the mixture is bubbling.
Remove from the heat and stir in the vanilla extract. Carefully drizzle the caramel evenly over the crackers.
Bake for 8 to 10 minutes until bubbling. The caramel will spread and fill any gaps during baking.
Remove from the oven and place the pan on a wire rack. Sprinkle the white chocolate chips evenly over the hot caramel. Let sit for 5 minutes until softened.
Spread the melted chocolate into an even layer. Top with the broken sandwich cookies and crushed peppermint candies.
Allow to cool completely, then refrigerate until set. Use the foil to lift from the pan and break into irregular pieces. Store at room temperature.