Preheat your oven to 375°F and line two baking sheets with parchment paper or silicone mats. While the oven heats, zest your lemons and squeeze the juice fresh—this makes a real difference in the brightness of both the cookies and icing. Measure out all your ingredients so everything is ready before you start mixing.

In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and ground nutmeg. Mix thoroughly to distribute the leavening agents evenly throughout the flour—this ensures your cookies will rise properly and bake uniformly. Set this dry mixture aside.

In a large bowl, beat the softened butter and sugar together for 2-3 minutes until the mixture is light, fluffy, and pale yellow in color. This creaming process incorporates air into the butter, which helps the cookies rise and creates a tender crumb. Take your time with this step—it's essential for the right texture.

Add the egg to the creamed butter mixture and beat for about 30 seconds until fully incorporated. Then add the vanilla extract, fresh lemon juice, and lemon zest from Step 1, mixing until the wet ingredients are well combined. The mixture should look smooth and bright yellow from the lemon.

Add the dry ingredient mixture from Step 2 to the wet mixture from Step 4, mixing on low speed or by hand with a spatula until just combined. Don't overmix—stop as soon as you don't see any white streaks of flour. Overmixing develops gluten and creates tough cookies instead of tender ones.

Using a cookie scoop or tablespoon, form the dough into 1.5-inch balls and place them about 2 inches apart on the prepared baking sheets. Bake for 10-12 minutes until the edges are light golden brown but the centers still look slightly underdone—they'll continue cooking as they cool. Remove from the oven and let the cookies rest on the baking sheet for 5 minutes before transferring to a wire rack.

While the cookies cool, whisk together the sifted confectioners sugar, lemon juice, lemon zest, and vanilla extract from Step 1 until you have a smooth, spreadable glaze. Once the cookies have cooled completely, spread or drizzle the icing over the top of each cookie. I find that letting the icing set for about 10 minutes before serving gives the cookies a lovely finished appearance.