Preheat the oven to 400 degrees. Line a sheet pan with parchment paper.

Measure 1 cup heavy cream and place it in the freezer for 10 minutes. Melt the butter in a microwave-safe bowl and let it cool slightly.

Whisk together flour, sugar, corn starch, poppy seeds, baking powder, baking soda, salt, and lemon zest in a medium bowl and set aside.

Combine the chilled heavy cream with the melted butter and stir until the butter forms small clumps.

Add the cream mixture to the dry ingredients and stir until all flour is incorporated.

Scoop the dough onto the prepared pan, spacing the scones at least 2 inches apart.

Refrigerate unbaked scones for at least 15 minutes.

Bake for 12-20 minutes or until light golden brown; transfer to a wire cooling rack.

Combine powdered sugar, milk (or half and half), and lemon juice in a medium bowl; whisk until smooth.

Spoon the glaze over the warm scones and allow any excess to drip onto a sheet pan.

Let the glaze set before serving.