Preheat oven to 425 F. Line a rimmed cookie sheet with aluminum foil. Fill sheet with all 40 saltine crackers in a single layer.
In a medium saucepan over medium-high, melt butter and brown sugar together and bring to a boil. Stir occasionally until combined and sugar is melted.
Then boil undisturbed for 5 minutes.
Remove from heat and pour caramel mixture over the cracker layer. Spread with a wooden spoon if needed to cover them evenly.
Bake in preheated oven for 4-5 minutes, or until just bubbly.
Remove from oven and sprinkle immediately with chocolate chips. When chips begin to melt, spread them over crackers with an icing spatula. Transfer pan to refrigerator until firm, about 2 hours. Break into pieces and store in an airtight container.
You can use club crackers, soda crackers, or Ritz crackers instead of the Saltines.
If you like white chocolate, replace the regular chocolate and smash up some candy canes to sprinkle on top!
Instead of pretzel topping, try your favorite chopped nuts.