Preheat your oven to 350°F (175°C) and grease a 9×13 inch baking dish.
In a medium bowl, combine the sugar cookie mix with the melted butter and egg. Press the dough evenly into your prepared baking dish and bake for 12-15 minutes.
In a separate mixing bowl, beat the softened cream cheese and powdered sugar together until smooth. Fold in whipped topping and spread over the cooled cookie crust.
Whisk the instant vanilla pudding mix with milk until thickened. Add vanilla extract and spread over the cream cheese layer.
Top with additional whipped topping and spread evenly.
Sprinkle festive sprinkles and crushed peppermint candies over the whipped topping.
Cover and refrigerate for at least 4 hours before slicing and serving.
Slice into squares and serve chilled.
Notes
Chill the layers for at least 4 hours to ensure proper setting and texture.