Prepare the crust: Mix graham cracker crumbs, sugar, and melted butter. Press firmly into the bottom of a springform pan. Chill for 15 minutes.
Make the filling: Beat cream cheese until smooth. Add sugar and flour. Mix in eggs one at a time, followed by sour cream, vanilla, and lemon juice.
Bake: Pour filling into crust. Place the pan in a water bath (to avoid cracks). Bake at 160°C (325°F) for 60–70 minutes, until the edges are set but the center jiggles slightly.
Cool: Turn off the oven, crack the door, and let the cheesecake rest for 1 hour. Refrigerate at least 4 hours or overnight.
Serve: Slice with a hot knife for clean edges, and enjoy plain or topped with fruit.