Start by crushing about 24 Oreo cookies in a food processor until you have fine crumbs, which should take around 1-2 minutes. Then, melt ½ cup of unsalted butter and combine it with the cookie crumbs in a mixing bowl. Mix thoroughly until the crumbs are well-coated, then firmly press the mixture into the bottom of a 9×13-inch baking dish to form a solid crust.

In a large mixing bowl, beat 8 ounces of softened cream cheese and 1 cup of powdered sugar together using an electric mixer until the mixture is completely smooth and creamy, which should take about 2-3 minutes. Once well-combined, set this mixture aside while you whip the heavy cream for the next layer.

In a separate bowl, pour 1 cup of heavy cream and add 1 teaspoon of vanilla extract. Use an electric mixer to whip the cream until stiff peaks form, which should take approximately 3-5 minutes. Once whipped, carefully fold this fluffy cream into the cream cheese mixture, creating a light and airy layer that you will spread over the crust.

In another bowl, whisk together 1 package of instant vanilla pudding mix and 2 cups of milk until the mixture thickens, which will take about 2 minutes. Once thickened, pour the pudding mixture evenly over the cream cheese layer, smoothing it out to create an even top.

If desired, sprinkle a generous layer of mini marshmallows over the pudding layer, distributing them evenly to add texture and sweetness. Gently press the marshmallows into the pudding layer with the back of a spoon.

Cover the baking dish with plastic wrap and refrigerate your No-Bake Christmas Oreo Lasagna for at least 3 hours. This chilling time is essential for the layers to set properly.

Once chilled, remove the lasagna from the refrigerator and gently peel back the plastic wrap. To finish, generously sprinkle crushed peppermint candies or Mini M&Ms on top and garnish with whole Oreos around the edges before slicing and serving.