Preheat oven to 350℉. Line cookie sheet with foil.
Cover cookie sheet with a single layer of saltines or pretzels. Ensure the crackers or pretzels are all touching. Vertically crease the foil on the pan to create a sort of dam around the crackers or pretzels.
Place brown sugar and butter in a pot over high heat and bring to a boil, stirring occasionally. Once it has reached a full boil, boil for 5 minutes without stirring. Pour mixture evenly over saltines/pretzels.
Immediately bake in oven for 7 minutes, until caramel has darkened and started to bubble.
Remove from oven and carefully ensure caramel is evenly spread with a spatula. Quickly sprinkle chocolate chips on top. Allow to melt for about 2 minutes or until glossy, then spread with spatula until evenly coated.
While chocolate is still hot, sprinkle on any desired toppings. Place pan into fridge overnight to cool, then break into pieces and enjoy.
Notes
*I prefer mini chocolate chips as they melt faster and spread better.