In medium bowl, cream butter and sugar until light and fluffy.
Beat in eggs one at a time. Add vanilla.
In separate bowl, stir together flour, baking powder and salt in small bowl.
In small bowl, mix candied ginger, cranberries, white chocolate and remaining teaspoon of orange zest.
Divide dough into two pieces. On lightly floured surface, shape each piece into a 12-inch / 30 cm long log.
Place logs on parchment lined cookie sheet, leaving enough room between them to allow for spreading during baking. Brush logs with egg white and place in oven.