Preheat oven to 350 degrees F. Cover cookie sheet with foil. Spray foil with cooking oil spray.
Place crackers on foil in 5 x 7 inch rows.
Microwave butter on high for 2 minutes. Add brown sugar and stir. Microwave on high for 2 more minutes, stirring every 30 seconds.
Pour over crackers. Bake 17 – 20 minutes (should bubble but not burn).
Sprinkle chocolate chips over hot crackers. Spread after 2 minutes (chips have softened).
Refrigerate 1 hour. Break into pieces.