Generously butter the inside of a 12-inch springform pan. Wrap a double layer of heavy-duty aluminum foil tightly around the outside bottom and sides of the pan, pleating and crimping it to seal. This will protect the cheesecake from water leaks during the bain-marie (water bath) baking process.
Position the oven rack in the center and preheat to 400°F (200°C).
Step 2: Make the Cheesecake Batter
In a large mixing bowl, use an electric mixer to beat the eggs and sour cream together until well blended and smooth. This step forms the creamy foundation for the cheesecake.
In a separate medium bowl, beat the cream cheese and butter together until light, fluffy, and completely lump-free. Scrape down the sides of the bowl to ensure an even texture.
Add the cream cheese and butter mixture to the egg and sour cream mixture. Beat until completely smooth and uniform.
Next, add the sugar, cornstarch, vanilla extract, lemon juice, and lemon zest. Continue to beat for about 3 minutes, until everything is fully incorporated and the batter is silky. The lemon brightens the richness of the cheesecake while cornstarch ensures a stable, creamy structure.
Step 3: Bake in a Water Bath
Pour the batter into the prepared springform pan, spreading evenly with a spatula. Tap the pan gently on the counter to remove any trapped air bubbles.
Set the springform pan inside a large roasting pan or baking dish. Place it in the oven and carefully pour very hot tap water into the roasting pan until it reaches halfway up the sides of the cheesecake pan. The water bath ensures gentle, even heat and prevents cracks on the surface.
Bake for about 3 hours and 20 minutes, or until the cheesecake is very lightly golden and a knife inserted into the center comes out clean. The surface should look set but slightly wobbly in the center — it will firm up as it cools.
