Reduce the oven temperature to 325°F. Prepare the water bath by placing a folded towel in the bottom of a large roasting pan or baking dish (make sure the springform pan fits in there comfortably with space on all sides).
In a large mixing bowl or the bowl of a stand mixer, combine granulated sugar, brown sugar and lemon zest and beat for 1 to 2 minutes or until fragrant.
¾ cup granulated sugar, ¼ cup light brown sugar, 2 tablespoons lemon zest
Add one package of cream cheese, and beat on low speed until smooth and creamy, scraping down the sides and bottom of the bowl as needed. Repeat with the remaining two blocks of cream cheese, beating until creamy between each addition.
24 ounces cream cheese
Add in the sour cream (or Greek yogurt if using), lemon juice and lemon extract (if using) and beat in on lows speed until fully combined, scraping the sides and bottom of the bowl often.
⅔ cup sour cream, 3 tablespoons lemon juice, 1 to 2 teaspoons lemon extract
Add in the eggs, one a time, beating on low speed, just until combined. Do not over beat.
3 large eggs
Fold in the fresh blueberries, if using. (Some prefer the cheesecake to be only lemon and the topping blueberry.)
1 cup blueberries
Wrap the springform pan in 2 layers of heavy duty aluminum foil to prevent water from getting in. I like to use the wide aluminum for extra protection.
Transfer the cheesecake mixture into the cooled crust and use an offset spatula to create an even layer. Tap the pan – gently – several times on the counter to pop any air bubbles.
Carefully place the springform pan on the folded towel in the roasting pan and place it in the oven.
Once the pan is in the oven, carefully pour the hot water into the baking pan, away from the cheesecake, until it reaches about the middle of the springform pan, at least 1 to 2 inches. (This water bath ensures that the cheesecake bakes evenly and helps reduce the possibility of cracking.)
Bake for 65 to 80 minutes or until the cheesecake has just a slight jiggle in the middle when the springform pan is moved. Start checking every three minutes after 65 minutes has passed. The cheesecake should reach 145°F when measured with a digital thermometer. If the cheesecake begins to crack, turn off the oven.
Turn off the oven, crack open the door and leave the cheesecake in the oven for 60 minutes. It will continue to cook while the oven cools.
Transfer the cheesecake to a cooling rack and let it set at room temperature for 60 minutes.
Cover with plastic wrap and chill in the refrigerator overnight (or for a minimum of 4 hours).