Melt the Butter: Start by melting ½ cup of unsalted butter in a saucepan over low heat. Once it's completely melted, remove it from the heat and let it cool to room temperature.

Prepare Lemon-Sugar Mixture: In a large mixing bowl, combine 1 cup of granulated sugar with the zest of two fresh lemons. Rub the zest into the sugar until fragrant.

Combine Wet Ingredients: Pour cooled melted butter into the lemon-sugar mixture. Add 1 large egg and 1 teaspoon of vanilla extract, mixing until smooth and slightly fluffy.

Mix Dry Ingredients: In a separate bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking powder, ½ teaspoon of baking soda, ¼ teaspoon of salt, and 2 tablespoons of poppy seeds. Gradually incorporate into wet mixture, stirring until just combined.

Chill the Dough: Use a cookie scoop to portion the dough into balls on a parchment-lined baking sheet. Cover with plastic wrap and chill in the refrigerator for 30 minutes.

Bake the Cookies: Preheat your oven to 180ºC (355ºF). Bake the chilled cookies for 10-11 minutes, until edges are golden and centers are still soft.

Cool the Cookies: Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.

Make the Cheesecake Frosting: Whip together 8 ounces of full-fat cream cheese, 1 teaspoon of vanilla extract, 1 cup of powdered sugar, and 2 tablespoons of heavy cream until stiff peaks.

Frost the Cookies: Once cookies are cool, frost the tops with the cheesecake frosting. Decorate with additional poppy seeds or lemon slices as desired.