Preheat the oven to 350°F (175°C / fan ovens 165°C).
Sift the flour, baking powder, salt and ginger into a medium bowl. Set aside.
Cream the butter and 1 cup sugar together in an electric mixer until light and fluffy.
Beat in the egg and egg yolk.
With the mixer on medium speed, add the lemon zest, lemon extract and the squeezed lemon juice.
With the mixer on low, gradually add the flour mixture, blending the mixture well until smooth. (Do not beat at this point.)
Cover the dough and put it in the fridge for at least 10 minutes and up to half an hour.
After the dough is chilled, pour the ½ cup sugar into a plate or bowl with raised edges.
Roll the chilled dough into balls about 1 inch in circumference between the palms of your hands.
Roll each cookie in sugar.
Place each cookie about two inches apart on baking trays or cookie sheets.(You may need to bake the cookies in batches.)
Bake for 10 to 12 minutes or until just beginning to turn a light golden shade. Keep an eye on the cookies so they do not burn.
Remove the baking trays from the oven and allow the cookies to cool for five minutes before carefully removing with an egg lifter or spatula.
Cool completely on wire racks (if you can resist them!).
When cool, store in a sealed container at room temperature. Makes about 3 dozen cookies.