In a medium bowl, whisk the flour, baking powder, baking soda, and salt together. Set aside.

In a large bowl, combine the granulated sugar and lemon zest. Rub the zest into the sugar with your fingertips to enhance the flavor.

Add the softened butter to the sugar and zest mixture. Use an electric mixer on high speed to cream the butter, sugar, and zest for 1-2 minutes, until light and fluffy.

Add the egg and vanilla extract to the bowl, then mix on medium speed until the mixture becomes pale and fluffy, about 1-2 minutes.

Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined.

Scoop 2 tablespoons of dough and roll into balls. Roll the dough balls in the prepared lemon sugar.

Place the dough balls 2 inches apart on the prepared baking sheets. Slightly flatten each ball into a circle.

Bake the cookies in batches of 6-8 for 9-10 minutes or until the edges are lightly golden.

Let the cookies cool on the baking sheets for 5 minutes before transferring them to a cooling rack to finish cooling.