Line a 10 x 15 cookie sheet with foil and spray with nonstick cooking spray.

Lay the graham crackers in an even layer covering the bottom of the pan. Set aside.

Preheat the oven to 350 degrees.

In a medium sized saucepan, place the butter, brown sugar, pecans, salt and cinnamon and bring to a boil over low/medium heat, stirring constantly.

Once the mixture begins to boil, keep stirring for 2 minutes. Remove from heat and add the vanilla and mix.

Pour the mixture over the top of the graham crackers, trying to spread it in an even layer.

Place the pan in the oven and bake for 10 minutes.

Remove and let the bark cool completely before breaking into smaller serving sized pieces.