Place a large mixing bowl and the beaters of your hand mixer (or the bowl of your stand mixer) in the fridge or freezer for 10–15 minutes to chill.
Add the softened cream cheese to the chilled bowl. Beat on medium speed for 1–2 minutes, until smooth and creamy, scraping down the sides as needed.
8 oz cream cheese
Add the powdered sugar, vanilla extract, and salt. Beat until the mixture is smooth, fluffy, and slightly lighter in color.
3/4 cup powdered sugar, 2 teaspoons pure vanilla extract, 1/4 teaspoon fine sea salt
Pour the cold heavy whipping cream into the bowl with the cream cheese mixture. Start beating on low, then increase to medium-high and whip for 3–5 minutes, until stiff but fluffy peaks form. The mixture should hold its shape but still look smooth and creamy.
3 cups heavy whipping cream
Taste the whipped cream filling and, if you prefer it sweeter, beat in an additional tablespoon or two of powdered sugar.
3/4 cup powdered sugar
Set aside 6–8 Oreo cookies for topping. Keep them whole for now. Pour the milk (if using) into a shallow dish for quickly dipping the remaining Oreos when assembling.
1 family-size package Oreo cookies, 1/2 cup milk, 6-8 Oreo cookies
In a 9×13-inch baking dish, arrange a single, even layer of Oreo cookies across the bottom. If using milk, give each cookie a very quick dip (about 1 second per side) before placing it in the pan. Break a few cookies as needed to cover the edges.
1 family-size package Oreo cookies, 1/2 cup milk
Spoon about one-third of the whipped cream filling over the Oreo layer. Spread it evenly to the edges with an offset spatula or the back of a spoon.
Add a second layer of Oreo cookies (dipping in milk if using), followed by another one-third of the whipped cream. Repeat with a third Oreo layer and finish with the remaining whipped cream spread evenly on top.
1 family-size package Oreo cookies, 1/2 cup milk
Crush the reserved Oreos in a zip-top bag with a rolling pin or crumble them by hand. Sprinkle the crushed cookies evenly over the top. Add chocolate shavings, mini chocolate chips, or a drizzle of chocolate sauce if desired.
6-8 Oreo cookies, chocolate shavings or mini chocolate chips
Cover the pan tightly with plastic wrap or foil. Refrigerate for at least 4 hours, or overnight for the best soft, cake-like cookie texture and clean slices.
When ready to serve, slice the cake into squares with a sharp knife, wiping the blade between cuts for neat layers. Garnish with fresh berries or extra whipped cream and chocolate sauce if you like.
fresh berries or chocolate sauce