In a medium bowl, beat the softened cream cheese with granulated sugar until smooth and creamy. Mix in the egg yolk and vanilla extract until just combined. Do not overmix. Cover the bowl and chill in the refrigerator for at least 20 minutes while you prepare the cookie dough. This helps it firm up for easier handling.

In a small bowl, whisk together the all-purpose flour, baking soda, and salt. Set aside.

In a large bowl with a stand mixer (or using a hand mixer), cream together the softened unsalted butter and granulated sugar on medium speed until light and fluffy, about 2-3 minutes.

Add the large egg, lemon zest, and lemon juice to the butter mixture, beating until well combined. Scrape down the sides of the bowl as needed.

Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix. Fold in the poppy seeds by hand.

Cover the cookie dough bowl with plastic wrap and chill in the refrigerator for at least 30 minutes. Chilling makes the dough easier to handle and prevents the cookies from spreading too much.

Preheat your oven to 375°F (190°C). Line two baking sheets with parchment paper.

Using a 1.5 tablespoon cookie scoop, scoop out portions of the chilled cookie dough. Flatten each scoop slightly into a disc in the palm of your hand.

Take about 1 teaspoon of the chilled cheesecake filling and place it in the center of the flattened cookie dough disc. Carefully bring the edges of the cookie dough up and over the filling, sealing it completely. Roll gently into a ball.

Place the filled cookie balls 2 inches apart on the prepared baking sheets. Repeat with the remaining dough and filling.

Bake for 10-12 minutes, or until the edges are lightly golden and the centers are set. The cookies will be soft when they come out of the oven. Let them cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.

Once the cookies are completely cooled, prepare the glaze. In a small bowl, whisk together the powdered sugar and 2 tablespoons of fresh lemon juice until smooth. If the glaze is too thick, add more lemon juice 1/2 teaspoon at a time until you reach your desired drizzling consistency.

Drizzle the lemon glaze over the cooled lemon poppy seed cheesecake cookies. Let the glaze set for a few minutes before serving.