Adjust the oven rack to the middle position and preheat the oven to 400 degrees.

In the bowl of a food processor fitted with the steel blade or in the bowl of an electric mixer fitted with the paddle attachment, combine the flour, sugar, and baking powder, and pulse or mix on low to incorporate. Add the lemon zest and butter, and pulse on and off, or mix on low, until the mixture is pale yellow and the consistency of a fine meal.

Transfer the mixture to a large bowl and stir in the ginger. Make a well in the center and pour in ½ cup cream. Using one hand, draw in the dry ingredients, mixing until just combined. If the mixture feels dry, add the remaining cream.

Wash and dry your hands and dust them with flour. Turn the dough out onto a lightly floured work surface and gently knead a few times to gather it into a ball. Roll or pat the dough into a circle about ¾ inch thick. Cut out the circles, cutting as closely together as possible and keeping the trimmings intact.

Gather the scraps, pat and press the pieces back together, and cut out the remaining dough. Place the scones 1 inch apart on a parchment-lined baking sheet.

Brush the tops with the remaining cream.

Bake for 12 to 16 minutes, until the surface cracks and they are slightly browned.