01 - Combine bread flour, sourdough starter, water, and salt in a large bowl. Mix until a shaggy dough forms. Cover and let rest for 30 minutes.
02 - Perform 2-3 sets of stretch and folds over 1.5 hours, resting 30 minutes between each set. After the final fold, cover and refrigerate overnight for 8-12 hours.
03 - Generously oil a 9x13-inch baking pan. Transfer chilled dough to the pan, stretching gently to fit. Cover and let rise at room temperature for 2-3 hours until very puffy.
04 - Beat cream cheese, sugar, egg yolk, vanilla, and lemon zest in a medium bowl until smooth and creamy. Set aside.
05 - Toss fresh raspberries with sugar and lemon juice in a small bowl. Set aside to macerate.
06 - Preheat oven to 425°F.
07 - Dimple the risen focaccia dough with oiled fingers. Dollop cheesecake mixture evenly over the surface, then gently swirl with a knife or spatula. Scatter raspberries and their juices across the dough.
08 - Drizzle additional olive oil over the surface. Bake for 25-30 minutes until golden brown, set, and edges are crisp.
09 - Let cool for at least 30 minutes before slicing. Serve warm or at room temperature.