Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large bowl, cream together the softened butter and sugar until light and fluffy.

Add the egg, lemon zest, and lemon juice. Mix until combined.

In another bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. If using, fold in the white chocolate chips.

Scoop the dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes, or until the edges are lightly golden. The centers may look slightly underbaked, but they will firm up as they cool.

Cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely