Preheat oven to 150°Celsius.
Break the cookies into crumbs by processing them in a food processor or by putting them in a zip lock bag and pressing them with a rolling pin. Place the crumbs in a bowl, add the castor sugar and melted butter, and mix until all the ingredients are well combined.
Transfer the crust mix into a parchment paper-lined 7 inches round springform pan and press it down evenly and firmly. Set aside. In a separate bowl, beat cream cheese until smooth for 30 seconds.
Scrape the sides of the bowl, add the sugar, flour, salt, lemon zest, and lemon juice and beat again for 20 seconds.
Scrape the bowl. Add in both the eggs and vanilla essence. Beat for about 10 seconds until the eggs are just combined. Scrape the bowl and continue beating for another 10 seconds until the batter is all smooth and creamy. Do not overbeat to avoid the batter from incorporating too much air.
Fold in the sour cream with a spatula until it is evenly combined into the batter.
Pour the batter into the prepared crust and bake in a water bath for 60 minutes at 150 degrees Celsius. When done, the sides should be firm and the center of the cake still wobbly. Turn the oven off and leave the cake in the oven for another 10 minutes.ated.
Remove from oven and let the cake cool for another 20 minutes before loosening the cake tin and removing the cake out. Let the cake rest in the refrigerator for at least 4 hours or overnight before serving.
Garnish the top with sour cream before serving. Keep leftovers refrigerated.