Preheat the oven to 350°F. Spray a 9-inch pie dish with cooking spray.

Place the Oreo cookies in the bowl of a food processor and pulse until finely ground. Add in the melted butter and pulse until moistened. Press the mixture into the bottom and up the sides of the prepared pie dish. Bake for 10 minutes, or until fragrant and set. Let cool completely on a wire rack.

In a small saucepan combine the sugar, corn syrup, salt, and 6 tablespoons of water and bring to a boil. Cook, without stirring, until a candy thermometer inserted into the syrup reads 340°F. Remove the pan from the heat and cautiously whisk in the butter and cream (the mixture will bubble up) until smooth. Whisk in sour cream. Let cool for 10 minutes then pour the caramel into the cooked crust. Refrigerate until firm, 1 to 2 hours.

In a small saucepan, whisk together the sugar and eggs. Set over low heat and cook, whisking constantly, until the mixture reaches 160°F and coats the back of a metal spoon. Remove from heat and stir in the melted chocolate and vanilla until smooth. Cool to just warm, stirring occasionally.

Use an electric mixer, beat the butter until light and fluffy, about 2 to 3 minutes. Gradually add in the cooled chocolate mixture then beat on high speed for 5 minutes, or until light and fluffy.

In a clean bowl use an electric mixer to beat the cream until it begins to thicken. Add the sugar and beat until stiff peaks form. Fold into the chocolate mixture.

Pour the mixture over the caramel, smoothing evenly. Chill for 6 hours.

Use an electric mixer to beat the cream, sugar, and vanilla on high speed until stiff peaks form. Top pie with whipped cream and garnish with chocolate shavings.