These BIRD bakery lemon squares will truly be the best you've ever had. They're sweet with just the right amount of tang. I've searched the world over and have never found a lemon square that has the taste, texture and zing that ours does!
Technique tip: Use natural parchment to line the pan and be sure there's a 2-inch overhang on all sides. It will make your life so much easier when cutting the squares!
Swap option: At BIRD bakery, we use freshly squeezed lemon juice, but to simplify the recipe, bottled lemon juice will work just fine. Just be sure it's pure lemon juice with nothing artificial.
For the crust:1.
Preheat oven to 350°F. Position the rack in center on the oven.2.
Coat a 9- by 13-inch baking pan with nonstick cooking spray. Line pan with parchment paper, leaving a 2-inch overhang on all sides.3.
In the bowl of an electric mixer fitted with the paddle attachment, add in the butter. Mix on low for 30 seconds then add in the sugar and beat until smooth.4.
Slowly add in the egg, flour and vanilla, continuously scraping the bottom of bowl. Beat just until the mixture forms a smooth dough.5.
Once finished, evenly press the dough into the bottom and about 3/4 inch up the sides of the prepared pan.6.
Refrigerate the crust for 20 minutes, and then bake for 15 to 20 minutes until the crust is lightly browned. Set aside to cool.
For the filling:
In a large bowl, beat eggs and yolk until thick. Slowly add the sugar and zest and continue beating. Whisk in lemon juice and flour, alternating each ingredient until well combined.
Refrigerate the mixture for 20 minutes.
To assemble and bake:
When crust is slightly cool, pour the filling into the crust and bake until set, about 15-20 minutes. Cool to room temperature and then refrigerate about 1 hour.
Using parchment edges, lift from pan. Sift the powdered sugar over the top and cut into squares or bars.