1.Preheat oven to 180°C/160°C fan-forced. Grease oven trays; line with baking paper.
2.Beat the butter, sugar and egg in a small bowl with an electric mixer until combined. Stir in the sifted flour and ground ginger, in two batches. Stir in glace ginger.
3.Roll level tablespoons of dough into balls. Place about 3cm apart on trays; flatten with a fork. Bake the biscuits for about 15 minutes or until cooked through; cool on trays.