01 -
Preheat oven to 180°C (350°F). Line a 23x23cm (9x9 inch) baking pan with parchment paper, leaving overhang for easy removal.
02 -
In a food processor, combine flour, powdered sugar, and salt. Add cold cubed butter and pulse until mixture resembles coarse crumbs. Add vanilla if using and pulse briefly to incorporate.
03 -
Press the mixture firmly into the prepared pan, creating an even layer. Bake for 15-18 minutes until edges are lightly golden.
04 -
While crust is baking, whisk together sugar, eggs, lemon juice, and zest until smooth. Stir in mashed raspberries. Add cornstarch and flour, whisking until fully incorporated with no lumps.
05 -
Pour filling over the hot crust and return to oven. Bake for 20-22 minutes until filling is set but still slightly jiggly in the center.
06 -
Allow bars to cool completely at room temperature, then refrigerate for at least 2 hours to fully set.
07 -
Lift bars from pan using parchment paper overhang. Cut into squares, dust with powdered sugar, and garnish with fresh raspberries and lemon slices if desired.