Preheat your oven to 375 degrees F and line your cookie sheet with parchment paper.
Place a single layer of saltine crackers on the cookie sheet, and cover the entire surface.
In a medium saucepan over medium heat, melt butter and brown sugar. Stir continuously until the mixture comes to a boil. Let it boil for 3 minutes then remove from heat, and stir in the vanilla extract.
Then pour the hot toffee mixture over the cracker layer, spreading it with a spatula and cover completely.
Bake in the preheated oven for 4-6 minutes or until the toffee is bubbling and has a rich, caramel color.
In a small microwave-safe bowl, melt the chocolate chips.
Remove from the oven and immediately pour the melted chocolate over the hot toffee. Spread evenly with a spatula.
While the chocolate is still soft, sprinkle toppings over the top.
Allow the crack to cool completely then cut into squares. Enjoy!