Preheat the oven to 375°F. Prepare a baking sheet with heavy-duty aluminum foil and spray with vegetable pan spray. Place crackers on the prepared baking sheet in an even layer.
Melt the butter in a saucepan over medium heat, then stir in brown sugar and bring to a boil, stirring often. Let mixture boil for 1-2 minutes, until sugar is fully dissolved. Remove the mixture from the heat and stir in vanilla.
Melt the butter in a saucepan over medium heat, then stir in brown sugar and bring to a boil, stirring often.
Carefully pour the sugar mixture over the crackers then spread evenly, making sure crackers are covered completely.
Bake in the oven for 5-7 minutes or until the topping bubbles.
Remove from the oven and place on a cooling grid to cool for 10 minutes.
In a medium bowl, melt Dark Cocoa Candy Melts Candy according to package instructions. Spread melted Candy Melts Candy over the crackers evenly then immediately sprinkle with sprinkles.
Let toffee bark stand on the cooling grid for 10 minutes then refrigerate for 30-45 minutes until fully set.
Remove saltine toffee bark from the baking sheet and break into pieces to serve.