Pre-heat the oven to 425°F and line an 8-inch x 8-inch baking dish with parchment paper.
Cover the bottom of the pan with Ritz crackers; it does not have to be pretty; just fit them in there in a single layer.
Using a sauce pan, combine the brown sugar and butter; bring to a boil; boil for 3 minutes without stirring.
Immediately pour the mixture over the Ritz crackers in the pan; use a spatula to spread evenly over the crackers.
Place in the pre-heated oven and bake for 5 minutes to thicken and set the caramel.
Remove from the oven; sprinkle the chocolate chips evenly over the top.
Place the pan back in the oven for about 2 minutes or until the chocolate is soft enough to spread.
Remove from the oven; using a spatula, immediately spread the melted chocolate until even on the top.
Top with candy of your choice, optional.
Allow to cool for several hours before removing from the pan and breaking it apart, otherwise it's a bit of a mess; feel free to place in the refrigerator for a bit to speed up the process.
Notes
Saltine crackers, in place of Ritz, make a great substitute.