Preheat your oven to 325°F (160°C). Grease or line a 9x9 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
In a mixing bowl, combine graham cracker crumbs, sugar, and melted butter until well combined.
Press the mixture evenly into the bottom of the prepared baking pan. Use the back of a spoon or a flat-bottomed glass to press the crust firmly.
In another mixing bowl, beat the softened cream cheese and sugar together until smooth and creamy.
Add eggs, one at a time, beating well after each addition. Stir in the vanilla extract, sour cream, and flour until smooth and well combined.
Pour the cheesecake filling over the prepared crust, spreading it out evenly with a spatula. Tap the pan gently on the counter to release any air bubbles. Place the pan in the preheated oven and bake for 40-45 minutes, or until the edges are set and the center is slightly jiggly.
Remove the bars from the oven and let them cool completely at room temperature. Once cooled, transfer the pan to the refrigerator and chill for at least 4 hours, or preferably overnight, to set completely.
Once chilled, use the parchment paper overhang to lift the cheesecake bars out of the pan. Cut into squares or bars. If desired, top each bar with fresh berries or fruit compote before serving.