Preheat oven to 325°F; mix graham cracker crumbs, 1/4 cup sugar, and butter, press into a greased 9-inch springform pan, and bake 10 minutes.
Beat cream cheese and 1 1/4 cups sugar until completely smooth with no lumps.
Mix in eggs one at a time, then stir in sour cream, vanilla, and flour until just combined.
Pour over crust and tap pan on counter to release air bubbles.
Bake 55-65 minutes until edges are set and center jiggles slightly like Jell-O.
Turn oven off, crack door open, and let cheesecake cool inside oven for 1 hour.
Refrigerate at least 6 hours or overnight, then remove springform ring and serve.