Lightly spray an 8” x 8” baking pan with cooking spray. Beat together room-temperature unsalted butter, all-purpose flour, and powdered sugar until crumbly. Press into the bottom of the prepared pan. Chill for 10-15 minutes.

Preheat your oven to 350°F (175°C). Bake the crust for 15-18 minutes until lightly golden. Let cool slightly.

In a large bowl, whisk together lemon juice, lemon zest, large eggs, granulated sugar, and sifted flour until smooth.

Pour the lemon filling over the cooled crust and spread evenly. Bake for 25-30 minutes, or until the filling is set but jiggly in the center.

Let the bars cool completely in the pan, then refrigerate for at least 1 hour before cutting.

Dust with powdered sugar before serving. Cut into squares and serve fresh or store in an airtight container for up to 5 days.