In a small bowl, beat cream cheese, powdered sugar, and lemon juice until smooth.
Drop 24 half-teaspoon sized mounds onto a parchment-lined tray and freeze for 30 minutes.
In a large bowl, cream butter and granulated sugar until light and fluffy.
Beat in the egg, lemon zest, and lemon extract.
In a separate bowl, whisk together all-purpose flour, baking soda, salt, and poppy seeds.
Gradually add the dry ingredients to the wet ingredients until just combined.
Scoop one tablespoon of dough, flatten it in your palm, place a frozen cream cheese dollop in the center, and wrap the dough around it to seal completely.
Place cookies on a parchment-lined baking sheet spaced 2 inches apart.
Bake at 350°F (175°C) for 10 to 12 minutes until the edges are set but the tops remain pale.
Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.