01 - Preheat oven to 350°F. Line two baking sheets with parchment paper for easy cleanup.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, and poppy seeds until evenly distributed.
03 - In a large bowl, beat softened butter and granulated sugar with an electric mixer until light and fluffy, approximately 2 minutes.
04 - Beat in the egg, lemon zest, lemon juice, and vanilla extract until fully incorporated and smooth.
05 - Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Avoid overmixing to prevent tough cookies.
06 - Scoop tablespoon-sized balls of dough onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading.
07 - Bake for 10 to 12 minutes, or until the edges are lightly golden. Allow cookies to rest on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
08 - In a medium bowl, beat softened cream cheese and butter together until smooth and creamy, scraping down the sides as needed.
09 - Add sifted powdered sugar, lemon juice, vanilla, and salt. Beat until light and fluffy, approximately 2 to 3 minutes.
10 - Once cookies are completely cool, spread or pipe a generous layer of cheesecake frosting onto each cookie. Optionally garnish with extra lemon zest or a sprinkle of poppy seeds.