Preheat oven to 400 degrees.

Line a 15-17 inch rimmed cookie sheet or jelly roll pan with aluminum foil and spray generously with cooking spray.

Place your graham crackers on your cookie sheet in a single layer.  (How many you use will depend on the size of your pan. I usually use around 14 sheets and if there is a little space around the edges, I just pull up the foil to the edges of the crackers to help keep that toffee on the top!)

In a large saucepan, bring your butter and brown sugar to a low boil over medium high heat and then stir continuously for 4-5 minutes.

Remove from heat and immediately stir in your vanilla extract.

Pour the hot mixture over your crackers, spread evenly with an offset spatula and bake for 5 minutes until it's bubbling all over.

Remove from oven, sprinkle your chocolate chips immediately on top of the crackers, let them sit and soften for a few minutes, then spread chocolate evenly on top of crackers.

Sprinkle with the sprinkles and mallow bits (or substitute any toppings you like.)

Let cool then move to the refrigerator to chill.  After a couple of hours, remove from the foil and break up into bite size pieces.

Store in an airtight container for up to one week!  (It never lasts that long in my house!)