Preheat the oven to 350°F. Grease a 10-inch springform pan, and line with parchment paper.
In a bowl combine crushed Oreos and 1 tablespoon of sugar. Melt the butter, and add to the crushed Oreos.
1½ cup Finely crushed chocolate Oreos, 1 tablespoon Sugar, ½ cup Butter
Using the bottom o a measuring cup, press the crumb mixture onto the bottom of the pan and about 1inch up the sides of the pan. Bake in the oven for 10 minutes.
How To Make The Filling
Melt the chocolate on a double boiler.
4 ounce Semisweet chocolate
In a food processor break down the cream cheese. Make sure it is lump-free. Add the sugar, sour cream, and vanilla extract. Mix well until the mixture is smooth and lump-free.
3 Blocks Cream Cheese, 1 cup Sugar, 1 cup Sour Cream, tbsp Vanilla extract
Add the flour and mix.
2 tablespoon Flour
Transfer the mixture to the bowl of the stand mixer, and set it on a low speed. Add the eggs, one at a time, then add the egg yolk and mix gently.
3 Eggs, 1 Egg yolk
Pour filling over the baked crust. Drop small dollops of melted chocolate over the filling and with the tip of a knife marble the chocolate. Place the pan in a shallow baking pan (see how to make the water bath). Bake for 50-60 minutes or until a 2-½-inch area around the outside edge appears set, but the center still jiggles, when gently shaken.