Preheat the oven to 350°F. Grease a 9x13-inch baking dish with non-stick cooking spray and set aside.
To a large mixing bowl, add 3 cups crushed cookies and melted butter. Stir until the cookie crumbs are coated evenly with butter.
Use your fingers to press the crumb mixture into the bottom of the prepared baking dish. Place the pan on the center rack of the preheated oven and bake for 10 minutes. Remove pan from the oven and transfer to a wire cooling rack.
Filling
To another large mixing bowl, add dry pudding mix and milk. Whisk until the pudding is soft set, about 2 minutes. *See Notes. Add in the orange gelatin and optional food coloring, and whisk again to combine.
Assembly:
Spoon the pudding mixture over the top of the cooled cookie crust; use an offset spatula to spread in an even layer.
Spoon cool whip over the pudding mixture, then sprinkle crushed Oreos over the top of the cool whip, covering it completely. Garnish with halloween candies.
Cover the dish with a layer of plastic wrap and place into the fridge to chill for 8 hours before serving.
Store in an airtight container in the fridge for up to 4 days.
Notes
Salted butter - Unsalted butter may be used, but you will need to add 1/4 teaspoon of salt to the crust mixture.When mixing the filling, be sure to whisk until the pudding is partially set. If the pudding isn’t set well enough before you layer it into the dessert, it won’t set completely in the fridge, and your lush dessert will be runny.Orange food coloring may be used if you wish for the pudding layer to be a more vibrant orange. Just simply add a few drops at a time while mixing, until the desired color is reached.