Preheat oven to 350°F. Pulse the Oreo cookies and sugar in a food processor to make fine crumbs. Add the melted butter and pulse until combined. Press the mixture into the bottom of 9 x 3-inch springform pan with removable bottom. Bake for about 10 minutes. Cool completely. Reduce oven temperature to 325°F.

Using an electric hand mixer or stand mixer fitted with the paddle attachment, mix together the cream cheese, sugar and sour cream until well combined, for about 2 minutes. Beat in the eggs, one at a time, mixing well after each addition. Mix in the vanilla (or raspberry extract) and pour into your prepared crust.

Set the springform pan on a piece of wide heavy-duty aluminum foil. Fold the foil carefully up the sides of the pan without tearing it. Set the pan in a large baking dish or roasting pan and pour in enough boiling water to reach halfway up sides of the springform pan.

Bake for one hour at 325°F. Turn off the oven and prop the door ajar with the handle of a wooden spoon. Let cool in the oven for 1 hour. Remove from oven and let cool completely. Remove carefully from springform pan.

Place the chopped chocolate in a small bowl and set aside. Heat the heavy cream in a small saucepan over medium-low heat. Cook until small bubbles appear on the outside edge of the cream. Pour the hot cream mixture over the chocolate. Using a wire whisk, gently stir from the middle out, until all of the chocolate is melted and the mixture is smooth. Allow the chocolate ganache to cool slightly and then pour over the cheesecake.

Top cheesecake with fresh raspberries and dust with confectioners' sugar if desired. Enjoy!