Preheat oven to 350°F. Prepare a baking sheet by lining it with aluminum foil and spraying the foil with nonstick cooking spray.

Arrange the crackers on the baking sheet so that there are no empty spaces in between them. Crush any remaining crackers into small crumbs and set aside for now.

Place the butter and brown sugar in a small saucepan over medium high heat. Stir while the butter melts, and bring the mixture to a rolling boil. Once boiling, carefully pour the sugar butter mixture over the crackers on the baking sheet in an even layer, trying to cover most of the crackers. If you miss some spots, don't worry as the toffee will spread in the oven.

Bake the toffee crackers at 350°F for five minute, until the toffee is bubbling all over. Carefully remove the pan from the oven and allow to cool for one minute.

Sprinkle the chocolate chips on top of the hot toffee, and allow them to sit for one minute to soften and melt. One softened, use an offset spatula or knife to spread the melted chocolate over the entire surface of the toffee in an even layer. While the chocolate is still sticky, sprinkle the top with the reserved crushed crackers.

Refrigerate the pan to set the toffee an chocolate for about 30 minutes. One set, break into small uneven pieces by hand and enjoy! Store any uneaten toffee in an airtight container for up to a week.