I have been making these little treats for years and they are a favorite of my family. It is one of those recipes, however, you can't make correctly when it's rainy, they just won't turn out right and you must follow recipe exactly according to the times given.
Preheat oven to 350 degrees. Boil butter and sugar 2 minutes. In the mean time, break apart graham crackers into singles and place in a single layer on baking sheet, it's ok if they touch, just not too crowded. Pour cooked mixture over graham crackers, coating evenly. Sprinkle pecans over coated graham crackers. Bake 10 minutes. Remove from oven and let set 1 minute - no longer! Remove from baking sheet to parchment paper or waxed paper to cool.