Preheat oven to 325°F. Prepare 10-inch springform pan with vegetable pan spray.
In medium bowl, combine the graham cracker crumbs, sugar and butter until well blended. Press into bottom of prepared pan; set aside.
Beat cream cheese and sugar with electric mixer on medium speed until smooth and creamy, about 5 minutes, scraping down bowl several times. Add eggs, one at a time, beating well after each. Add orange extract; blend well. On low speed, add sour cream until just combined, and then slowly pour in heavy cream, beating until smooth.
Remove 1/4 cup of batter to a small bowl. Stir in 1-2 drops of Wilton Orange Color Right Base Color. Pour remaining filling over crust. Drop spoonfuls of orange batter over and swirl together with small knife or spatula.
Place cheesecake in center of oven. Fill a large, deep pan with hot water and place on rack underneath cheesecake. Bake for 1-1/2 hours or until center of cheese only jiggles slightly. Turn off oven and let cheesecake stand for 30 minutes. Remove from oven and cool completely. Refrigerate until ready to serve. Top with orange slices if desired.