Preheat oven to 325.
Line an 11x7 pan with nonstick foil.
Stir oreo crumbs, sugar and butter.
Press into pan and bake 10 mins.
Cool completely!
In a mixer, beat cream cheese, sugar, flour and cocoa until smooth.
Add egg and yolk.
Add sour cream and vanilla.
Make sure you scrape down the sides.
Slowly pour in the melted chocolate.
Carefully spread this over the crust and smooth the top.
Bake 45 mins.
Cool to room temp and then chill a few hours.
Cut into squares and dip into the melted chocolate.
Lay on a cookie sheet lined with parchment and chill in fridge to firm up chocolate.
Add a drizzle if desired.
Keep chilled and serve at room temp!