Preheat your oven to 350°F (175°C).
Cream the softened butter and granulated sugar in a large bowl until light and fluffy.
Add the egg, lemon juice, and lemon zest, and stir until combined.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Drop tablespoon-sized balls of dough onto a parchment-lined baking sheet, spaced 2 inches apart.
Bake for 12-15 minutes or until the edges are lightly golden.
Let them cool on the baking sheet for 5 minutes before transferring to a wire rack.
Dust with powdered sugar before serving.