Place room temperature cream cheese in large bowl of standing mixer and mix until smooth. Add 1 cup of the sugar, lemon zest, lemon juice and sour cream and mix until combined.
If you decide to separate the egg whites to make stiff peaks, do it at this stage, otherwise skip this step and follow the next. Separate the eggs and beat the egg whites until stiff peaks, set aside. Add egg yolks in the cream cheese mixture and combine. Incorporate the egg whites with the spatula in the cream cheese mixture.
Add in one egg at a time (total of 4 eggs) and incorporate the eggs into the mixture. Do not over mix at this stage. Scrape the sides of the bowl.
Pour the cream cheese mixture into prepared 9" spring form pan and bake until the centre is slightly wobbly, about 55-60 minutes. If you are using water bath, don't forget to cover the spring form pan with the aluminum foil and place it in deep baking dish with hot water. Bake as directed above. If you decide using the method removing the cheesecake out of the oven during baking:When the cake has risen in the oven for the first time, which will take just few minutes 5 or 7 minutes. Remove the cheesecake from the oven and reduce slightly the temperature of the oven. Let the surface of the cheesecake to sink to level with the top of the pan, then put the cheesecake back to the oven, repeat this twice during the baking.
Turn off the oven and open the oven door at first crack (1/4 opened door) and allow the cake to cool in the oven for 1 hour.
Remove the cheesecake from the oven and run a small paring knife around the edges of the cake, let it sit for 1 hour on kitchen counter.
When the cheesecake is cooling, mix in medium bowl, sour cream, sugar and vanilla extract and pour it over the cheesecake. Even the sour cream topping with spatula or knife. Cover the cheesecake with food foil and place it in the refrigerator.