01 - Preheat the oven to 350°F. Line a 9-inch square baking pan with parchment paper, leaving an overhang on the sides.
02 - Combine graham cracker crumbs, melted butter, sugar, and salt in a bowl until mixture resembles wet sand. Press evenly into the bottom of the prepared pan. Bake for 10 minutes, then allow to cool slightly.
03 - In a small saucepan, cook raspberries, sugar, and lemon juice over medium heat for 4 to 5 minutes, stirring and mashing until thickened. Strain through a fine sieve if desired to remove seeds. Let cool.
04 - Beat cream cheese and sugar in a large bowl until smooth and creamy. Add eggs one at a time, mixing well after each. Stir in vanilla extract and sour cream. Fold in melted white chocolate and flour until just combined.
05 - Pour cheesecake filling over cooled crust and smooth the surface. Drop raspberry sauce over the filling in spoonfuls and swirl gently with a skewer or knife.
06 - Bake for 30 minutes, until edges are set and center remains slightly wobbly. Cool to room temperature, then refrigerate for at least two hours before cutting into bars.