Preheat oven to 350°F.
Make the crust: Grind the Oreos in a food processor until they are a fine crumb. Reserve 2 tablespoons of crumbs (15 g). Place in a bowl and stir in melted butter with a fork. Press into the bottom and up the sides of 9-inch or 10-inch springform pan. Chill until ready to fill.
Make the filling: Place butter and semi-sweet chocolate in a medium sized bowl. Melt in the microwave, heating on high in 30 second increments, stirring between each, until the chocolate is melted and smooth.
Once the chocolate is melted and smooth, whisk in the flour, sugar, vanilla, and salt. Whisk in eggs and egg white, one at a time, until the mixture is smooth. Pour mixture into prepared crust.
Place pan on a cookie sheet in case some of the butter leaks out of the springform pan. Bake until the top is puffed, and filling is set in the center, 35-45 minutes. Let cool 1 hour. The top will fall a bit, this is normal.
Once the pie has cooled for about an hour, make the topping: Place the white chocolate and heavy whipping cream in a medium sized microwave safe bowl. Heat for 1 minute, then whisk until white chocolate melts into the cream. Add the peanut butter and whisk or stir until smooth.
Spread the filling over the pie. Sprinkle with reserved cookie crumbs.
You can let this set overnight at room temperature or you can chill to set.
Serve the pie at room temperature for ultimate gooiness (if it’s cold it will be more like fudge).