01 - Preheat oven to 350°F. Line a 10x15 inch baking sheet with aluminum foil and coat with non-stick cooking spray.
02 - Lay Saltine crackers in a single, even layer covering the entire bottom of the prepared baking sheet.
03 - Melt butter in a medium saucepan over medium heat. Stir in brown sugar and salt, then bring to a boil. Continue stirring and let the mixture bubble for 3 minutes. Remove from heat and stir in vanilla extract.
04 - Immediately pour the hot toffee mixture over the cracker layer, spreading it evenly with a spatula to coat all crackers.
05 - Bake for 7-8 minutes, or until the toffee layer is bubbling across the entire surface.
06 - Remove from oven and immediately scatter white chocolate chips in an even layer over the hot toffee. Let rest for 2 minutes until softened, then gently spread the melted chocolate into a smooth, even layer.
07 - Combine granulated sugar and ground cinnamon in a small bowl, then sprinkle the mixture evenly across the warm white chocolate surface.
08 - Allow the toffee to cool completely at room temperature for about 40 minutes, or refrigerate to speed up setting. Once firm, break into irregular pieces.