1/2 cup (1 stick, 113 grams) unsalted butter, softened to room temperature
1/2 cup (100 grams) granulated sugar
1 cup (125 grams) all-purpose flour
pinch of salt
1 1/2 tablespoons poppy seeds
For the Topping:
3 large eggs
1 cup (200 grams) granulated sugar
2 teaspoons fresh lemon zest
3 tablespoon (25 grams)s all-purpose flour
1 tablespoon corn starch
1/2 cup fresh lemon juice
Powdered sugar and poppy seeds for topping
Place a rack in the upper third of the oven and preheat oven to 350 degrees F. Grease a 9×9-inch baking pan, line with parchment paper (so that it over hangs slightly from the pan) and grease the parchment paper. Set aside.
To make the crust, in the bowl of a stand mixer fitted with a paddle attachment cream together butter and sugar until light and fluffy, 3 to 5 minutes. Stop the mixer and scrape down the sides of the bowl. Add flour, salt and poppy seeds. Beat on low speed until dough is incorporated. Dough may come together, but if it remains shaggy, that’s fine too.
Dump the crust into the prepared pan and use your fingertips to press the dough into the bottom of the pan. Bake for 15 to 18 minutes until just browned around the edges.
You can make the filling while the crust is baking. In a medium bowl, whisk together eggs and sugar until well combined and slightly thick. Sift the flour and cornstarch over the egg mixture and whisk in. Add the lemon juice, and zest and whisk until blended.
Pour the filling over the still warm baked crust. Return to the oven and bake for 18 to 20 minutes, or until lightly browned on top and no longer jiggling in the center.
Allow to cool completely in the pan. Run a knife around the edges of the pan. Slice lemon bars into 9 or 12 squares squares. Use the over hanging parchment paper to lift the squares out. To store the lemon bars, place them in an airtight container separated by wax paper layers. Dust with powdered sugar and poppy seeds before serving.