Crush Oreo cookies in a food processor until fine crumbs form, or place in a plastic bag and crush with a rolling pin. Mix crushed cookies with melted butter until mixture resembles wet sand.

Press the Oreo mixture firmly into the bottom of an 8x8 inch Pyrex dish using the bottom of a measuring cup. Freeze for 10 minutes while preparing the chocolate layer.

Prepare chocolate pudding using only 1 cup of milk (half the amount typically called for on package). Whisk until thick and smooth, then gently fold in 1/2 cup Cool Whip until no white streaks remain.

Spread chocolate pudding mixture evenly over the chilled Oreo crust. Return to freezer for 10-15 minutes to set slightly.

Beat softened cream cheese, sugar, 2 tablespoons milk, and vanilla extract with an electric mixer until completely smooth with no lumps, scraping down sides of bowl as needed.

Fold raspberries into the cream cheese mixture, then gently fold in 1 cup Cool Whip until combined.

Spread raspberry mixture carefully over the chocolate layer, using a spatula to reach edges and create an even surface.

Top with remaining Cool Whip (1-2 cups for generous coverage), spreading smooth or creating decorative swirls. Cover and refrigerate for at least 4 hours or overnight before serving.

For cleanest slices, wipe knife clean between cuts. Garnish individual slices with fresh raspberries and chocolate shavings if desired.