Preheat your oven to 400 degrees Fahrenheit.
Line a baking sheet (15" x 10") with aluminum foil and spray with cooking spray to avoid sticking.
Place crackers in an even layer. (This was 7 rows by 6 rows with Club Crackers)
In a medium saucepan, melt butter and brown sugar over medium heat, stirring often.
Bring to a boil and boil for approximately three minutes, stirring constantly.
Remove from heat and stir in vanilla if desired. Pour toffee mixture over top of crackers. Spread evenly over top with a spatula. Bake uncovered for 5 minutes.
Remove from heat and top evenly with chocolate chips. Wait 5 minutes to melt chocolate chips. (Place in warm oven for one to 2 minutes if needed to melt chocolate chips further if needed)
Gently spread chocolate out over toffee using a spatula.
Immediately top with any toppings such as pretzel pieces, small candies, dried fruit, sprinkles, coconut or nuts.
Cool 10 minutes before transferring to the refrigerator. Refrigerate at least 2 hours or until very firm. Break into larger pieces. Store cracker toffee in an airtight container for up to two weeks.
