Zest the lemon into the sugar and use your fingers to rub it into the sugar.
Whisk together the flour, poppy seeds, salt and baking powder
Grate the frozen butter into the flour mixture toss to coat the butter.
Add the cold heavy cream and mix it into the dry ingredients
Shape the dough into an 8-inch circle and cut it into 8 wedges. Chill the unbaked scones for at least 30 minutes.
Brush the scones with egg wash and bake the scones at 400F until dark golden brown.
Let the scones cool before adding the glaze. Or serve them warm without the glaze.