01 - Preheat oven to 350°F. Line a 9×9-inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
02 - In a medium bowl, combine graham cracker crumbs, granulated sugar, and melted butter until the mixture resembles wet sand. Press firmly and evenly into the bottom of the prepared pan. Bake for 8 minutes, then set aside to cool slightly.
03 - Using an electric mixer, beat softened cream cheese and sugar together in a large bowl until completely smooth and creamy. Add eggs one at a time, beating well after each addition. Blend in vanilla extract and sour cream until just combined—do not overmix.
04 - Pour the cheesecake filling over the partially cooled crust, spreading into an even layer with a spatula.
05 - In a separate bowl, toss diced peaches with sugar and lemon juice until coated. Distribute the peaches evenly over the cheesecake batter and gently press them into the surface.
06 - Bake for 30 to 32 minutes, or until the edges are lightly golden and the center is set but still has a slight jiggle. Avoid overbaking—the center will firm up as it cools.
07 - Cool completely at room temperature, then transfer to the refrigerator and chill for at least 2 hours until thoroughly set.
08 - If using the topping, beat heavy whipping cream with powdered sugar using an electric mixer until soft peaks form.
09 - Lift the chilled cheesecake from the pan using the parchment overhang. Slice into 12 even bars and top each with a dollop of whipped cream before serving.