Start by creaming together the butter, cornstarch, and confectioner’s sugar in a mixing bowl using an electric mixer. Beat them until they are well-combined and fluffy, which should take about 3 minutes. You'll notice the mixture becoming lighter in color and texture—this is a sign you're on the right track!
Next, add the all-purpose flour to the butter mixture. Mix until just combined; it’s crucial to avoid over-mixing at this stage. The dough should come together without any dry flour visible. You want it to be soft and slightly sticky but still manageable.
Now, it’s time to incorporate the fresh flavors! Add the lemon zest and lemon juice into the dough. This step is where the magic happens; the zesty smell will make your mouth water. Beat the mixture until everything is thoroughly mixed, and a soft dough forms.
Divide the dough in half and turn each half out onto a piece of parchment or waxed paper. Shape each piece into a 1-inch roll, twisting the ends of the paper to seal it. This method ensures your cookies will have a uniform shape once baked. Refrigerate the rolls until they are firm—about 1 hour is perfect!
When it's time to bake, preheat your oven to 350ºF (175ºC). Line a rimmed baking sheet with parchment paper to prevent the cookies from sticking.
Slice the chilled dough into 1/4-inch thick rounds. Arrange them on the prepared baking sheet, leaving some space in between as the cookies will spread slightly.
Bake the cookies in your preheated oven for about 10 minutes. You’ll know they’re done when they are set, but don’t expect any browning—this is key. Remove them from the oven and allow them to cool on the baking sheet for a few minutes before transferring them to a wire rack.
While the cookies cool, prepare the glaze. In a medium mixing bowl, combine another 1/2 cup of confectioner’s sugar, the additional lemon zest, and lemon juice. Stir until the glaze is smooth and free of lumps.
Once the cookies are completely cooled, spoon about 1/2 teaspoon of the glaze onto the center of each cookie, spreading it gently with the back of the spoon. The glaze adds a lovely shine and an extra layer of lemony flavor. Allow the glaze to set before serving—this will make for a lovely presentation!
