Preheat your oven to 400°F (200°C) and line two baking sheets with parchment paper.

Chill 1 cup of heavy cream in the freezer for about 10 minutes. Melt 1/2 cup of butter.

In a large mixing bowl, combine the all-purpose flour, sugar, cornstarch, poppy seeds, baking powder, baking soda, salt, and lemon zest.

Pour the chilled heavy cream into the bowl with the melted butter and mix until small clumps form.

Gently add the wet mixture to the dry ingredients, stirring until just incorporated.

Portion out the dough onto the prepared baking sheets, placing them about 2 inches apart. Refrigerate for at least 15 minutes.

Bake for 12 to 20 minutes until golden brown. A toothpick inserted should come out clean.

Cool on the baking sheets for 5 minutes, then transfer to a wire rack to cool completely.

Whisk powdered sugar, milk, and fresh lemon juice until smooth to prepare the glaze.

Drizzle the glaze over cooled scones and allow to set before serving.