Step 1: Prepare the Pan

1. Line a 9×9-inch square pan with parchment paper, leaving overhang for easy removal. Set aside.

Tip: Ensure parchment covers sides for easy lifting; lightly grease the pan to help parchment stick.

Step 2: Make the Oreo Crust

1. In a food processor, blitz 600 g Oreo cookies into fine crumbs (or place in a zip-top bag and crush with a rolling pin).
2. Weigh out 100 g (½ cup) crumbs and set aside for the ice cream filling.
3. Transfer remaining crumbs to a medium bowl, add 170 g melted unsalted butter, and stir until the mixture resembles wet sand.
4. Press half the Oreo mixture into the prepared pan using a spatula or the bottom of a small cup to form a flat, even layer.
5. Freeze the crust for 15–20 minutes while preparing the ice cream. Keep the remaining Oreo mixture warm (e.g., near the stove).

Tip: Press firmly for a sturdy crust; keep the second half of the mixture soft for easy spreading later.

Step 3: Make the Ice Cream Filling

1. In a large mixing bowl, use an electric hand mixer to beat 500 g heavy cream and 1 Tbsp vanilla extract until stiff peaks form (3–5 minutes).
2. Slowly fold in 150 g condensed milk with a spatula until no streaks remain.
3. Gently fold in the reserved 100 g Oreo crumbs until just combined.

Tip: Whip cream to stiff peaks but avoid over-beating; fold gently to keep the mixture airy.

Step 4: Assemble the Layers

1. Pour the ice cream mixture over the chilled Oreo crust and smooth into an even layer with an offset spatula.
2. Freeze for 1–2 hours until the surface is firm to the touch.
3. Gently spread the remaining Oreo crust mixture over the ice cream, pressing lightly with a flat-bottomed cup to form an even layer (avoid pressing too hard to prevent sinking).

Tip: Ensure the ice cream is firm before adding the top crust; spread gently to maintain layers.

Step 5: Freeze and Slice

1. Freeze the assembled pan for at least 6 hours or overnight until fully set.
2. Lift the ice cream block out using the parchment overhang.
3. Run a sharp knife under hot water, wipe dry, and cut into 8 rectangular slices.

Tip: Warm the knife for clean cuts; work quickly to prevent melting.

Step 6: Serve

1. Serve immediately or wrap individual sandwiches in parchment and return to the freezer.

Tip: Serve straight from the freezer for firm texture; offer with a dusting of powdered sugar or chocolate drizzle for extra flair.