Line a 9-in x 13-in baking pan with aluminum foil so that the bottom and sides of the pan are fully covered. If one piece of foil doesn’t cover both, use two placing one in the pan longways and the other perpendicular to it. Press the foil into the pan so that it is flush. Spray liberally with cooking spray and set asie.

Place flour, sugar, cornstarch, and salt into a food processor. Process until combined, about 15 seconds.

Place the butter into the food processor and process until the dough is pale yellow and resembles a coarse meal, about 30 to 60 seconds. The dough will still be a bit crumbly but the butter shouldn’t be visible.

Sprinkle the dough into prepared pan and press firmly using fingers, creating a layer about ¼ inch thick on the bottom and ½ inch thick on the sides.

Place the pan in the refrigerator for 30 minutes to chill and preheat the oven to 350 F.

Bake for 20-25 minutes, until crust is golden brown. While the crust is baking, prepare the filling.

Once baked, place pan on a wire rack and let cool about 5 minutes before filling. Reduce oven temperature to 325 F.

In a medium bowl, whisk eggs, sugar, and flour together.

Stir in the lemon zest, lemon juice, milk and salt.

Once crust has cooled briefly, stir the mixture to reblend and pour into the warm crust.

Bake for 20-30 minutes, until the filling feels firm when lightly touched.

Transfer the pan to a wire rack and let cool completely.

Cut cooled lemon bars into 3-inch circles using a round cookie cutter.

Gently place stencil on top of a lemon round and, using a small fine mesh strainer, lightly dust with powdered sugar.

Keep in an airtight container in the refrigerator for up to 2 days.