Preheat the oven to 325°F (163°C). Lightly grease a 9-inch springform pan and set aside.
Make the crust: in a bowl combine the Graham Cracker Crumbs, Granulated Sugar, and a pinch of Salt. Stir in the melted Unsalted Butter until the mixture resembles wet sand, then press it firmly and evenly across the bottom (and slightly up the sides, if desired) of the prepared pan. Chill the crust in the fridge while you prepare the filling.
Beat the Cream Cheese in a large bowl on medium speed until very smooth and free of lumps, scraping the bowl as needed.
Add the remaining Granulated Sugar and continue beating until light and creamy, then mix in the All-Purpose Flour until incorporated.
Reduce the mixer speed and blend in the Sour Cream until smooth. Add the Eggs one at a time, mixing gently after each just until combined to avoid incorporating too much air.
Fold in the Vanilla Extract, Lemon Juice, and Lemon Zest, and taste for balance—add a small additional pinch of Salt if needed to enhance the flavors.
Pour the filling over the chilled crust and smooth the top with a spatula. Tap the pan gently on the counter to release any large air bubbles.
Prepare a water bath: wrap the outside bottom of the springform pan in a double layer of foil to prevent leaks, place the pan in a larger roasting pan, and carefully pour very hot water into the outer pan until it reaches about halfway up the sides of the springform.
Bake for about 50–70 minutes, until the edges are set and the center still slightly jiggles when the pan is gently shaken—the center will finish setting as it cools.
Turn off the oven, crack the door open, and let the cheesecake cool inside for 1 hour to prevent sudden temperature changes. Remove from the water bath, unwrap the foil, and finish cooling to room temperature on a wire rack.
Refrigerate the cheesecake at least 4 hours, preferably overnight, before removing the springform rim. Run a thin knife around the edge to loosen before releasing the ring. Slice with a hot, clean knife for clean cuts and serve chilled.
