Preheat oven to 350°F.
Line a large baking sheet with heavy duty aluminum foil (if using regular foil, spray with non-stick cooking spray for easy removal).
Spread the crackers out on the foil in a single layer and fold up the edges of the foil to box in the crackers.
Set aside.
In a small saucepan, melt the butter and brown sugar over medium-high heat on the stovetop.
Bring to a rolling boil.
Reduce the heat to medium and continue to boil for 5 minutes (set a timer), stirring occasionally.
Quickly pour over the crackers and spread to cover completely.
Bake for 5 minutes in the oven.
Turn off heat.
Remove from oven and immediately sprinkle the chocolate chips on top.
Let stand for 1-2 minutes or until the chocolate starts to look shiny and is soft enough spread evenly over the toffee.
If the chocolate is still not warm enough to spread after 4 minutes, place it back in the oven for a minute to help soften it.
Top with any additional toppings if desired.
Chill in the refrigerator for about 2 hours to harden.
Peel away the foil and break into pieces.