In a heavy metal saucepot combine the sugar, water, and lemon juice. Over high heat cook the sugar to a deep caramel color and pour out into a round 9-inch cake pan, turning around the perimeter so as to cover the sides and bottom of the pan. Set aside to cool completely while you make the cake.
Preheat the oven to 325 degrees F.
In mixer fitted with a paddle attachment, on low speed work the cream cheese until smooth. Add the sugar, vanilla, and orange zest. Continue to mix for 2 minutes until smooth. Add the eggs, 1 at a time, and scrape down after each addition.
On low speed slowly stream in the heavy cream. Scrape down every 30 seconds. Remove from bowl and pour out into prepared cool caramel pan.
Bake in a hot water bath for 1 hour. When finished the cake will be slightly firm to the touch. Remove from the oven and place in the refrigerator. Make sure to cool down for at least 4 hours before flipping over. The cake can be made up to 2 days in advance.
Flip over by placing a 12-inch flat plate over the top of the cake pan. Hold with a firm grip and flip cake upside down. Let the pan sit on top for a second. Lift pan off the cake and serve on its own or with berries.