Preheat your oven to 400°F. Line a 10x15-inch baking sheet with aluminum foil and lightly grease it with cooking spray.
Arrange the Saltine crackers in a single layer on the prepared baking sheet, covering the entire surface.
In a medium saucepan over medium heat, melt the butter. Once melted, stir in the brown sugar and bring the mixture to a boil. Allow it to boil for 3 minutes without stirring, then remove from heat and stir in the vanilla extract.
Pour the butter and sugar mixture evenly over the Saltine crackers, spreading it gently with a spatula to cover all the crackers.
Bake in the preheated oven for 5-7 minutes, or until the toffee is bubbly. Remove from the oven and immediately sprinkle the chocolate chips over the hot toffee. Let them sit for a minute to soften, then spread the melted chocolate evenly over the top.
In a small bowl, mix the powdered sugar and cinnamon together. Sprinkle this mixture evenly over the chocolate layer.
Allow the toffee to cool at room temperature for about 30 minutes, then place it in the refrigerator for at least 1 hour to set completely. Once set, break into pieces and serve.