Preheat the oven to 375ºF (190ºC). Line a large baking sheet with parchment paper.
In a large bowl, whisk together the flour, baking powder, salt and sugar until well blended
Work the butter and lemon zest into the flour mixture with your fingertips or with a pastry blender until pea size chunks form.
Stir in the heavy cream and lemon juice until a shaggy dough is formed. If your dough seems too dry, you can add 1-2 more teaspoons of heavy cream.
Turn the dough out onto a lightly floured surface. Fold the dough over onto itself a couple of times. Do not overwork the dough.
Pat or roll the dough into an 8-inch round, about 3/4-inch thick. Cut out rounds using a 2" or 2 1/4" inch round cutter.**
Place the scones about 2 inches apart onto the prepared baking sheet. Brush the scones with heavy cream. Sprinkle generously with sparkling sugar.
Bake until the edges are golden brown, about 16-19 minutes.
Cool completely on a wire rack. Decorate with icing.