Put a single layer of saltine or graham crackers side by side (with 4 sides touching one another) on a 10 by 15-inch rimmed cookie sheet, lined with parchment paper.
Bring butter and brown sugar to a rolling boil. Boil for three minutes.
Spread mixture on top of crackers.
Preheat oven to 400 degree.
Bake crackers with sauce, for 5 minutes.
Remove from heat and immediately sprinkle with 1 1 /2 cups chocolate chips. Let set three minutes and then spread melted chips over with a butter knife.