In large bowl, beat cream cheese and sugar with electric mixer on medium speed until well combined. Add sour cream, heavy cream, eggs and vanilla and mix until thoroughly incorporated. Pour half of cheesecake mixture into separate small bowl. Add cocoa powder to remaining cheesecake mixture and mix on low speed until well incorporated. Pour half of plain cheesecake mixture into crust, then pour in half of chocolate mixture. Repeat with remaining plain and chocolate mixtures. Use a spatula or knife to swirl together.