Preheat oven to 350°F.
In a medium bowl, whip cream with an electric mixer until stiff peaks form, about 1 minute. Set aside.
Mix cornstarch and water in a small bowl until smooth. Set aside.
Place the cream cheese in the bowl of an electric mixer, beat on low speed for 2-3 minutes until smooth and free of any lumps. Add sugar and sour cream and continue mixing until incorporated. Gradually add sweetened condensed milk and beat until creamy, for 1-2 minutes. Add lemon juice, vanilla extract and cornstarch mixture; beat until well incorporated. Turn off mixer.
Add whipped heavy cream and gently foil in using a spatula. Pour the mixture over the crust; tap gently to remove any air bubbles.
Place the cheesecake pan on a large piece of aluminum foil and fold up the sides around it (this is to keep the water from seeping into the cheesecake). Place the cake pan in a large roasting pan. Pour hot water into the roasting pan until the water is about halfway up the sides of the cheesecake pan.
Bake for 40 minutes or until the edges are just barely puffed but the filling is pale—you're not looking for golden brown.
Turn off the oven and leave the door closed for 40 more minutes (leave the cheesecake inside of the oven). The cheesecake will continue to cook, but slowly begin to cool as well.
After 40 minutes, remove the cheesecake from the oven. The center of the cheesecake should still wobble when you remove it; it will continue to cook as it cools on the counter. Remove the cheesecake from the water bath and wrapping. Let it cool at room temperature. Then refrigerate for at least 4 hours, or overnight.
Loosen the cheesecake from the sides of the pan by running a thin metal spatula around the inside rim. Unmold and transfer to a cake plate.