Preheat oven to 350 degrees F (175 degrees C). Grease a jellyroll pan.
Arrange graham crackers side by side on the entire bottom of the jelly roll pan. In a small saucepan, cook the butter and brown sugar, stirring constantly until the sugar is dissolved. Bring to a boil and simmer for one minute. Remove from heat, stir in the vanilla, and pour the entire mixture evenly over the graham crackers. Sprinkle the pecans all over. Bake in the preheated oven for 10 minutes.
After removing cookies from the oven, sprinkle with the chocolate chips. Let stand until completely cool before cutting into bars. For best results, try to cut along the perforations of the graham crackers.
