Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a medium bowl, whisk together the flour, baking powder, and salt.
In a large bowl, beat the softened butter and cream cheese together until smooth and creamy.
Add the granulated sugar to the butter and cream cheese mixture and beat until light and fluffy.
Mix in the egg, vanilla extract, lemon zest, and lemon juice until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Drop tablespoon-sized balls of dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake for 10-12 minutes, or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
If desired, dust the cooled cookies with powdered sugar before serving.