Instructions:
- Preheat oven to 350°F (175°C). Grease and lightly flour a 9-inch springform pan. Wrap the outside bottom and sides of the pan securely in at least two layers of heavy-duty aluminum foil to waterproof it for the water bath.
- Make the Crust: Combine cracker crumbs, ¼ cup sugar, and melted butter. Press the mixture firmly and evenly into the bottom and about 1 inch up the sides of the prepared pan. Bake for 10 minutes. Remove and let cool completely. Reduce oven temperature to 325°F (160°C).
- Prepare the Water Bath: Place the foil-wrapped springform pan inside a large roasting pan. Set aside.
- Mix the Filling: Beat the softened cream cheese on medium speed until perfectly smooth. Gradually beat in the 1 ½ cups of sugar. Mix in the sour cream, vanilla, and lemon zest. Add the eggs one at a time, mixing only until just incorporated after each addition. Do not over-mix.
- Gently fold in the flour and salt using a rubber spatula until just combined.
- Assemble and Bake: Pour the filling over the cooled crust. Carefully place the roasting pan (with the cheesecake inside) onto the middle oven rack. Pour boiling water into the roasting pan until it reaches about 1 inch up the side of the springform pan.
- Bake for 70–80 minutes. The edges should look set, but the center 2–3 inches should still have a slight wobble.
- Crucial Cooling: Turn the oven off. Prop the oven door open slightly (using a wooden spoon handle) and let the cheesecake cool in the cooling oven/water bath for 1 hour.
- Final Chill: Carefully remove the cheesecake from the water bath, remove the foil, and let it cool completely on a wire rack at room temperature (about 1 hour). Once cool, cover loosely and chill in the refrigerator for at least 6 hours, but preferably overnight, before slicing.