Preheat oven to 400°. Line a large cookie sheet with foil and spray with nonstick cooking spray. Arrange saltines in a single layer in prepared pan.

Add butter and brown sugar in a small saucepan. Cook over medium high heat, stirring often, until it comes to a boil. Reduce heat to low and boil for 3 minutes (do NOT stir during this time). Immediately pour over crackers. Bake for 5-7 minutes.

Immediately sprinkle chocolate chips over the top and wait 2 minutes, until they become melty. Spread the chocolate even across the bars. Sprinkle with toffee chips and let cool completely. (It helps if you do this in the refrigerator.) Break into pieces.