Melt the unsalted butter in a small saucepan over low heat. Once completely melted, remove it from the heat and let it cool in the fridge until it reaches room temperature, about 10–15 minutes.

In a mixing bowl, add granulated sugar and lemon zest. Rub the zest into the sugar for about 2–3 minutes until fragrant.

Pour the cooled melted butter into the lemon-sugar mixture. Add the egg and pure vanilla extract, then mix until smooth and fully combined.

In a separate bowl, whisk together all-purpose flour, baking powder, baking soda, poppy seeds, and salt.

Gradually add the dry mixture to the wet mixture, stirring gently until just combined.

Use a cookie scoop to portion the dough into uniform balls on a lined baking sheet. Chill the dough in the refrigerator for about 30 minutes.

Preheat your oven to 355°F (180°C).

Remove dough from the refrigerator and place cookie balls on a parchment-lined baking sheet. Bake for 10–11 minutes until edges are lightly golden. Let cool on tray for a few minutes before transferring to a wire rack.

In a mixing bowl, combine cream cheese, powdered sugar, heavy cream, and agave or honey. Whip until stiff peaks form, around 3–4 minutes.

Once cookies are cooled, frost each cookie with the cream cheese mixture and decorate with poppy seeds and lemon slices.