• Adjust oven rack to the lower third position and preheat the oven to 350F degrees. Spray a 9-inch springform pan with nonstick cooking spray.

Make the crust:

• Crush cookies in a food processor or in a ziploc bag. IIn a bowl or food processor, pour melted butter on top of the crushed cookie and pulse or mix well.Place the oreo mixture at the bottom of a springform pan. Smooth out the mixture with the bottom of a measuring cup or glass. Wrap the bottom of the pan in a double layer of aluminum foil. Set aside.

Make the cheesecake:

• Using a handheld or stand mixer fitted with a paddle attachment, beat the cream cheese, powdered sugar and granulated sugar together on medium speed in a large bowl - about 3 full minutes until the mixture is smooth and creamy. Add the sour cream, vanilla, and almond extract and beat until combined. On low speed, add the eggs one at a time, beating after each addition until just blended. Do not overmix the filling after you have added the eggs. Set aside
• Place the springform pan into a large roasting pan and place into the oven. Fill with about 1 inch of hot water. The foil wrapped around the pan will prevent water from leaking inside. Bake for 65-75 minutes or until the center is almost set. If you find the edges are browning, loosely place aluminum foil on top of the cake as it bakes. Once done, turn the oven off and open the door slightly. Let the cheesecake sit in the oven for 1 hour. Remove from the oven and allow to cool completely at room temperature. Refrigerate for at least 6 hours or overnight (preferred).

Make the chocolate mousse:

• In a small bowl, melt the chocolate and butter together in the microwave, whisking every 30 seconds. Let cool. Stir in the egg yolks very slowly and carefully.
• In another bowl, beat the egg whites until foamy. Add the cream of tartar, and continue to beat. Gradually whisk in 1/4 cup sugar, and continue beating until stiff peaks form. In another bowl, beat heavy cream with the whisk attachment until it begins to foam and thicken up. Add the remaining 2 tablespoons sugar and vanilla. Continue to whip the cream until it holds soft peaks.
• Gradually and gently fold the egg whites into the chocolate mixture to lighten it. Then, delicately fold in the whipped cream. Take care not over work the mousse but make sure you blend in the cream well. Place the mousse on top of the cooled cheesecake while still in the springform pan and refrigerate.

Make the chocolate ganache:

• Heat the cream in a small sauce pan over medium heat. Heat it up just BEFORE it boils. Place the chocolate in the cream, and remove from heat. Stir the mixture until smooth. Pour over the chocolate mousse, return to refrigerator and chill for at least 2 hours before serving. Enjoy!