Heat up 3/4 cup of heavy cream in the microwave for about one minute until it's hot.

In a heat-safe bowl, place the chocolate chunks and pour the hot heavy cream over them. Let it sit for 5 minutes.

Whisk the melted chocolate and hot heavy cream until it becomes smooth. If needed, you can microwave it for an additional 15 seconds until it's fully melted.

Once the chocolate and heavy cream are well combined, stir in the vanilla extract and salt. Set it aside for approximately 30 minutes to cool.

Use a hand mixer or stand mixer to whip the remaining heavy cream and powdered sugar together until stiff peaks form, creating your whipped cream.

Gently fold the whipped cream into the chocolate and heavy cream mixture.

Carefully fold in the chopped Oreo cookies.

Scoop the mousse into small ramekins and refrigerate for 2-3 hours until set. For a softer texture, let it sit at room temperature for 15 minutes before serving.

Garnish with extra whipped cream, Oreo cookies, and chocolate shavings.