Makes 24 to 32 bars (9 x 13-inch pan)
XIAOLU'S NOTES: I like my lemon bars quite tangy so feel free to add another 1/4 to 1/2 cup of powdered sugar to the filling if you prefer yours sweeter. In case you're worried, the bars should turn out thicker than in my photo. That slice is thin because my oven is lopsided :(.
1 3/4 cups all purpose flour
2/3 cup powdered sugar, plus extra to garnish
1/4 cup cornstarch
2/3 tsp salt
1 tsp finely grated lemon zest
3/4 cup (1 1/2 sticks) unsalted butter, cool room temperature and cut into 1-inch pieces
1 1/2 cups sugar, or more according to personal taste
1 Tbsp finely grated lemon zest
6 Tbsp all purpose flour, sifted
1/3 cup lemon juice (from 2 lemons)
2/3 cup passion fruit puree
Preheat oven to 350 degrees F. Grease the sides of a 9 x 13-inch baking pan, line with parchment paper, then lightly grease parchment.
To make the crust, combine flour, powdered sugar, cornstarch, salt, and lemon zest in the bowl of a food processor. Add butter and pulse until the mixture is pebbly. Press evenly into the bottom of your prepared pan. Refrigerate for 20 to 30 minutes (optional but preferable. Bake until lightly golden, about 18 to 20 minutes. Set aside crust.
To make the filling, place the eggs and yolks in a medium bowl and whisk to combine. In a separate small bowl, combine the sugar and lemon zest and rub them together until fragrant. Now add the sugar mixture, salt, flour, lemon juice, and passionfruit puree to the egg mixture. Whisk until smooth. Pour this filling over the pre-baked crust and bake for another 25 to 30 minutes, or until just set. Let cool to room temperature, then refrigerate for at least 2 hours or until firm. Sift powdered sugar over the top before slicing and serving.