Preheat oven to 325°F.
Line springform pan with parchment paper.
Mix flour, baking soda, and spices in bowl.
Add carrots, sugar, oil, egg, and vanilla.
Stir until batter forms.
In another bowl, beat cream cheese until smooth.
Add sugar, eggs, vanilla, and sour cream.
Beat until creamy mixture forms.
Spread half carrot cake batter in pan.
Pour cheesecake mixture on top.
Drop spoonfuls of remaining carrot cake batter.
Swirl gently with knife for marble effect.
Bake for 55 minutes until set.
Cool on wire rack for one hour.
Chill in fridge for four hours minimum.
Frost if desired before serving.