01 - Preheat oven to 325°F. Line the bottom of a 9-inch springform pan with parchment paper and set aside.
02 - Combine graham cracker crumbs, melted butter, and sugar in a medium bowl until the mixture resembles wet sand. Press firmly and evenly into the bottom of the prepared pan. Bake for 10 minutes, then set aside to cool.
03 - In a large bowl, beat the softened cream cheese with an electric mixer on medium speed until completely smooth and free of lumps. Gradually add the granulated sugar, mixing until fully incorporated.
04 - Add the eggs one at a time, beating well after each addition. Blend in the sour cream, vanilla extract, flour, and lemon juice. Mix until just combined—avoid overmixing to prevent cracks.
05 - Pour the filling onto the cooled crust and smooth the surface with a spatula. Bake for 45 minutes, or until the edges are set but the center still has a slight jiggle.
06 - Turn off the oven, crack the door open slightly, and let the cheesecake rest inside for 1 hour. This gradual cooling helps prevent surface cracks.
07 - Remove the cheesecake from the oven and allow it to cool completely to room temperature. Refrigerate for at least 4 hours, preferably overnight, before serving.
08 - If using the topping, whisk together sour cream, powdered sugar, and vanilla extract until smooth. Spread evenly over the chilled cheesecake before slicing and serving.