Generously butter the inside of a 10-inch springform pan. Wrap the bottom and sides of the pan in a double layer of heavy-duty aluminum foil to prevent water from seeping in during baking.

Preheat your oven to 300°F (150°C) and position the rack in the center of the oven.

In a large bowl, beat 5 large eggs and 2 cups sour cream until smooth using an electric mixer.

In a separate bowl, beat 4 packages (8 oz each) of cream cheese and 8 tablespoons of unsalted butter until smooth and creamy, ensuring there are no lumps.

Combine the cream cheese mixture with the egg and sour cream mixture, beating until fully blended.

Gradually mix in 1 1/2 cups sugar, 2 tablespoons cornstarch, 1 1/2 teaspoons vanilla extract, 1 teaspoon fresh lemon juice, and 1 teaspoon grated lemon zest. Beat for about 2 minutes until smooth.

Pour the cheesecake batter into the prepared springform pan. Place the pan inside a large roasting pan and pour very hot water into the roasting pan until it reaches halfway up the sides of the springform pan.

Bake the cheesecake in the preheated oven for 2 hours and 15 minutes, or until the top is lightly colored and a knife inserted in the center comes out clean, with a slight jiggle in the middle.

Remove the springform pan from the water bath, peel away the foil carefully, and let the cheesecake cool at room temperature for about 4 hours.

Cover the cooled cheesecake and refrigerate overnight (or for at least 6 hours) for the best flavor and texture.

To serve, remove the cheesecake from the springform pan. Garnish with fresh fruit, whipped cream, fruit sauce, or a sprinkle of lemon zest as desired. Slice and enjoy!