No bake chocolate cheesecake

From Serious EatsWe made this for the girls' family birthday party and it rocked.  Like this version, this one is also no-bake and only needs a little work plus some time in the fridge before serving.

10 oz chocolate cookie wafers
2 tbs sugar
8 tbs unsalted butter, melted
3 8 oz packages of cream cheese
1 c plus 2 tbs powdered sugar
2 tsp vanilla extract
1/4 c sour cream
7 oz bittersweet chocolate, melted

Pulse cookies and sugar in a food processor until the cookies are broken into fine pieces.
Put in a bowl and pour in the melted butter, stir to combine.
Press into the bottom and up the sides of an 8 inch springform pan
In a stand mixer with the paddle attachment or with a hand mixer, beat the cream cheese and sugar together until light and creamy, about 1 minute.
With a low speed, add in the vanilla, sour cream and melted chocolate until smooth and combined.
Spoon mixture into the crust and chill for 4 hours.
Bring to room temperature, about 30 minutes, before serving.