In a large bowl, add the granulated sugar and lemon zest. Use your fingers to rub the zest into the sugar for enhanced flavor.

Whisk together the flour, baking powder, salt, ground ginger, and poppy seeds in the same bowl for about 30 seconds.

Grate the frozen butter into the mixture and gently toss to incorporate.

In a separate measuring cup, combine the heavy cream and lemon juice, then whisk well.

Pour the cream mixture into the dry ingredients, using a rubber spatula to mix until just combined.

Turn the dough out onto a floured surface and knead gently, incorporating any remaining flour until it forms a shaggy dough. Shape it into a square, about 8 x 8 inches.

Fold the dough in half and pat into an 8-inch square again, repeating this step twice.

Form the dough into an 8-inch circle, about 1 inch thick. Cut into 8 wedges.

Place the wedges onto a tray and refrigerate for at least 30 minutes. Preheat your oven to 400°F (200°C).

Assemble an egg wash by whisking together the egg and cream (or milk).

Place the chilled scones on a parchment-lined baking sheet, brushing with the egg wash.

Bake for 15-18 minutes until golden brown and they reach an internal temperature of 204°F (95°C).

Cool for 10 minutes before transferring to a wire rack; wait until they reach room temperature to add the lemon glaze.

To make the glaze, whisk powdered sugar with lemon juice until smooth, adjusting the consistency with more sugar or lemon juice as needed.