Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent sticking, then arrange the saltine crackers in neat rows to fully cover the sheet.
In a saucepan over medium heat, melt the butter and add the brown sugar. Stir constantly and bring the mixture to a boil. Continue boiling for 2-3 minutes, stirring frequently, until the mixture thickens and forms a caramel. Pour the hot caramel evenly over the arranged saltines, then use a rubber spatula to spread it into a smooth layer.
Place the baking sheet with the caramel-covered saltines in the preheated oven. Bake for 4-5 minutes, until the caramel is browned and bubbling. Carefully remove the sheet from the oven.
Immediately after removing the pan from the oven, sprinkle the semi-sweet chocolate chips evenly over the hot caramel layer. Let the chocolate chips sit undisturbed for 5 minutes to melt. Once melted, use a clean spatula to spread the chocolate into an even layer across all the crackers. I like to gently nudge the chocolate to the very edges, so every bite has a perfect chocolate layer.
While the chocolate is still warm and spreadable, top the surface with your favorite Halloween decorations. Distribute eye-shaped candy decorations, candy corn pieces, Reese’s Pieces, and Halloween-themed sprinkles freely over the chocolate. Feel free to get creative with your designs!
Place the decorated tray in the refrigerator for at least 1-2 hours, or until the chocolate has fully hardened. Once set, break the candy into pieces and enjoy. Any leftovers can be stored in a zip-top bag in the freezer for a sweet treat any time!