01 - Preheat oven to 325°F. Line a 9x9-inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
02 - In a medium bowl, combine graham cracker crumbs, 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.
03 - Combine strawberries, sugar, and lemon juice in a small saucepan over medium heat. Cook for 5–7 minutes, stirring and mashing the berries, until the mixture reduces into a thick syrup. Blend with an immersion blender until smooth and set aside to cool.
04 - In a large bowl, beat the cream cheese with an electric mixer until smooth and creamy. Add sugar and blend until incorporated. Add eggs one at a time, mixing well after each addition. Beat in vanilla extract, sour cream, and flour until just combined — do not overmix.
05 - Pour the cheesecake batter over the baked crust and spread evenly. Drop spoonfuls of the cooled strawberry puree across the surface. Use a knife or skewer to gently drag through the puree, creating a marbled swirl pattern.
06 - Bake for 30–35 minutes until the edges are set and the center has a slight jiggle. Remove from the oven and allow to cool at room temperature.
07 - Refrigerate the cheesecake bars for at least 2 hours until fully chilled and firm. Lift bars from the pan using the parchment overhang and cut into 16 squares to serve.