01 -
Preheat oven to 163°C and position rack in center. Spray a 23 cm x 23 cm baking dish with cooking spray and line with parchment paper, leaving a 5 cm overhang on two opposite sides.
02 -
Pulse graham crackers, egg white, melted butter, sugar, and salt in a food processor until fine crumbs form. Press evenly into bottom of prepared pan. Set aside.
03 -
Beat cream cheese in a stand mixer on medium-high speed until fluffy, 1 to 2 minutes. Add sugar and mix until combined. Incorporate the whole egg and reserved egg yolk one at a time, blending well after each addition. Add vanilla extract and whisk to integrate fully. Pour mixture over crust.
04 -
Gently mash fresh blueberries to retain some texture and fold in blueberry jam. Distribute dollops of blueberry mixture over the cream cheese filling.
05 -
Whisk together flour, brown sugar, melted butter, lemon zest, and salt until soft crumbs form. If mixture feels wet or warm, refrigerate until firm. Sprinkle evenly over blueberry layer.
06 -
Bake for approximately 30 minutes until edges are firm, center retains slight jiggle, and topping is lightly golden. Allow to cool in pan for 30 minutes.
07 -
Refrigerate bars until fully cold, at least 2 hours or overnight. Use parchment overhang to lift bars from pan and cut into portions.