Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper. Pulse Oreo crumbs and mix with melted butter, then press into the prepared pan. Bake for 10 minutes, then cool completely.

In a mixing bowl, whip 1 cup of heavy whipping cream on medium speed until soft peaks form. Add powdered sugar to taste and whip until stiff peaks are reached. Chill the whipped cream.

Melt 5 oz of semi-sweet chocolate chips with the remaining 5 tablespoons of butter over simmering water until smooth. Cool slightly.

Beat 6 oz of cream cheese until smooth. Gradually mix in powdered sugar, cocoa powder, vanilla extract, and salt. Add the cooled chocolate mixture and blend until smooth.

Fold in half of the whipped cream into the chocolate filling until combined, then fold in the remaining whipped cream.

Spread the chocolate filling over the cooled crust evenly. Cover the pan with plastic wrap or foil.

Chill the assembled bars in the refrigerator for at least 3 hours, ideally overnight.

Whip additional heavy cream until soft peaks form. Spread over the chilled bars and garnish with chocolate shavings.

Lift the bars from the pan using the parchment paper. Slice with a hot knife and serve cold.