Blueberry Cheesecake Bars with Crumble Topping

Instructions:

1. Preheat your oven to 350°F (175°C). Line an 8x8 inch square baking pan with parchment paper, ensuring enough overhang on the sides to create a sling for easy removal.
2. In a medium mixing bowl, combine the graham cracker crumbs, 85g melted butter, 25g granulated sugar, and salt. Press the mixture firmly into the bottom of the prepared pan.
3. Par-bake the crust for 10 minutes at 350°F to seal the surface. Remove from the oven and set aside while preparing the layers.
4. In a small saucepan over medium heat, combine blueberries, 25g sugar, lemon juice, and cornstarch. Simmer for 5-8 minutes until the berries burst and the mixture thickens into a jammy consistency. Set aside to cool.
5. In a large bowl, beat the softened cream cheese and 100g sugar until completely smooth. Add eggs one at a time, beating on low speed until just incorporated. Fold in the sour cream, vanilla, and lemon zest.
6. In a separate small bowl, combine flour and brown sugar. Cut in the 42g of cold cubed butter with a fork or pastry blender until the mixture resembles coarse crumbs.
7. Pour the cream cheese filling over the par-baked crust. Spoon the blueberry reduction over the filling and use a knife to swirl it gently.
8. Evenly distribute the crumble topping over the blueberry swirl.
9. Bake for 35-40 minutes at 350°F, or until the edges are set and the center has a slight jiggle.
10. Allow the bars to cool at room temperature for one hour, then refrigerate for at least 4 hours (or overnight) before slicing into 16 squares.