Preheat oven to 300°F (150°C). Grease a 9-inch springform pan.
In a large bowl, beat the cream cheese and butter together until completely smooth and creamy.
Mix in the sour cream until combined.
Add eggs one at a time, mixing well after each addition.
Stir in cornstarch, sugar, vanilla extract, lemon juice, and lemon zest. Beat until smooth and fully incorporated.
Pour the batter into the prepared springform pan and smooth the top.
Bake for 2 hours and 15 minutes, or until the center is set but still slightly jiggly.
Remove from the oven and let cool at room temperature for 3 hours.
Refrigerate for at least 1 hour before slicing and serving.
Enjoy!