Preheat oven to 325°F.
Boil a pot of water on the stove to have ready for the water bath once the filling is complete.
With the paddle attachment, mix the cream cheese, sugar and flour at MEDIUM speed for about 3 minutes. Scrape sides, bottom and paddle at least a couple of times to remove any clumped cream cheese.
Add in the vanilla, lemon zest, lemon juice, and salt for an additional minute, scraping sides, bottom and paddle halfway through and at the end.
Whisk eggs and sour cream in a separate bowl until well incorporated. Then, add to mixture on LOW speed. Scrape bowl, bottom and paddle. Mix BRIEFLY to combine: DO NOT OVERMIX!
Overlap a vertical and horizontal layer of foil and fold them up to the rim, but not touching it.
Pour cheesecake mixture in springform pan over the cooled crust and slightly jiggle it to level out the top. Place it in a large roasting pan and pour the boiling water AROUND the springform pan to about a 1-1/2" in depth.
Place on middle rack in the oven for 1 hour 30 minutes to 1 hour 45 minutes. Center should be slightly jiggly. DO NOT REMOVE FROM OVEN! Check temperature, if you can with an instant read thermometer. Temperatures above 150°F may affect texture.
TURN OVEN OFF and prop its door open, leaving the cheesecake on the oven rack allowing it to cool off gradually for 1 hour.
Remove to a cooling rack for another hour in the roasting pan. Remove from water bath and allow to continue to cool off until bottom of pan is barely warm.
Refrigerate covered with plastic or in a container overnight or at least 8 hours, before cutting.