01 - Preheat oven to 325°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, sugar, and melted butter, stirring 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 chopped strawberries, sugar, and lemon juice in a small saucepan over medium heat. Cook for 5–7 minutes, stirring frequently and mashing the strawberries as they soften, until the mixture reduces into a thick, syrupy consistency. Blend with an immersion blender until smooth, then set aside to cool completely.
04 - In a large bowl, beat the softened cream cheese with an electric mixer until smooth and creamy. Add sugar and blend until fully incorporated. Add eggs one at a time, mixing well after each addition. Beat in vanilla extract, sour cream, and flour until just combined — avoid overmixing.
05 - Pour the cheesecake batter over the baked crust and spread into an even layer. Drop spoonfuls of the cooled strawberry puree across the surface. Use a knife or skewer to gently drag through the puree and batter, creating a marbled swirl pattern.
06 - Bake for 30–35 minutes, or until the edges are set and the center has a slight jiggle. Remove from the oven and allow to cool at room temperature.
07 - Once cooled to room temperature, refrigerate the bars for at least 2 hours until fully chilled and firm. Use the parchment paper overhang to lift the slab from the pan, then cut into 16 even squares.