Pre-heat oven to 350°F.
Line cookie sheet or Bubble and Brown with wax or parchment paper and spray with non-stick spray.
Line cookiesheet with graham crackers to cover the entire bottom.
In saucepan, melt butter and brown sugar over medium heat, stirring constantly until it boils and thickens and has caramel texture.
Pour mixture over graham crackers and spread.
Bake in oven until bubbles (2-4 minutes).
Remove from oven and pour chocolate chips on top. Return to oven for a few minutes so chips will warm up.
Remove fromoven and spread chocolate chips over the graham crackers, sugar and butter mixture.
Sprinkle nuts and toffee bits on top. Put in freezer for an hour or more until cool.
Remove and twist cookie sheet to break the bark.