Bring cream cheese, sour cream, and eggs to room temperature for 1-2 hours before baking.
Preheat oven to 325°F. Line springform pan bottom with parchment, grease sides, and wrap exterior with heavy-duty foil to waterproof for water bath.
Mix graham cracker crumbs with sugar and melted butter until evenly moistened. Press firmly into bottom and 1 inch up sides of prepared pan. Bake at 325°F for 10 minutes, then cool. Reduce oven temperature to 300°F.
Place roasting pan on oven rack and bring water to a boil for the water bath.
Beat room-temperature cream cheese on low speed until smooth, about 2-3 minutes. Add sugar and flour and mix on low until incorporated. Add salt, lemon zest, and lemon juice. Mix in sour cream and vanilla until smooth.
Add eggs and egg yolks one at a time on lowest speed, mixing just until each is incorporated. Do not over-mix. Fold gently with spatula.
Pour filling over cooled crust and smooth top. Place springform pan in roasting pan, pour boiling water around it, and bake at 300°F for 1 hour 30 minutes until edges are set and center has a slight wobble.
Turn off oven and leave cheesecake inside with door cracked for 1 hour. Remove from water bath, loosen edges with knife, and cool completely on rack. Refrigerate at least 6 hours or overnight.
Remove from fridge 20 minutes before slicing. Run knife under hot water, wipe dry, and cut in smooth downward motion. Wipe blade between slices and serve.