Cheesecake Batter: Preheat oven to 350°F. Grease 10-inch springform pan and line sides with parchment paper.
Using electric mixer, beat cream cheese until smooth. Whisk together sugar and flour; beat into cream cheese until light and fluffy, scraping down sides of bowl as needed. Add eggs, one at a time, just until incorporated. Beat in sour cream; beat in vanilla. Set aside.
Carrot Cake Batter: Whisk together flour, cinnamon, baking powder, baking soda, nutmeg and salt until well combined; set aside. In separate bowl, beat together eggs, sugar, oil, applesauce and vanilla; stir into flour mixture just until moistened. Fold in carrots.
Scrape half of the carrot cake batter into bottom of prepared pan; smooth top. Dollop half of the cheesecake batter over top in large spoonfuls. Dollop remaining carrot cake batter in large spoonfuls around the cheesecake batter. Scrape remaining cheesecake batter over top; smooth top.
Bake for 50 to 55 minutes or until cheesecake is just set but still jiggly in center. (If top of cake starts to brown too quickly, tent loosely with foil.) Let cool completely in pan on rack. Cover and refrigerate for at least 4 hours or up to 8 hours.
Decorate with whipped cream and sprinkle with chopped walnuts.
TIP: Garnish top of cake with pecans, walnuts or toasted coconut.