01 - Preheat oven to 325°F. Line a 9x9-inch baking pan with parchment paper, leaving excess on the sides for lifting bars out easily.
02 - In a medium bowl, mix graham cracker crumbs with granulated sugar and melted butter until combined. Press the mixture firmly and evenly into the bottom of the prepared pan.
03 - With an electric mixer in a large bowl, beat cream cheese and granulated sugar on medium speed until very smooth. Add eggs one at a time, beating after each addition. Blend in vanilla extract and sour cream until fully incorporated.
04 - Pour the cheesecake batter over the prepared crust. Spread evenly with a spatula. Bake for 40 to 45 minutes, or until edges are lightly golden and the center is just set.
05 - Remove pan from oven and allow bars to cool at room temperature. Transfer to refrigerator and chill for at least 3 hours until fully set.
06 - Once chilled, top evenly with chopped strawberries and blueberries. Optionally, drizzle with melted white chocolate. Slice into bars and serve cold.