In a medium bowl, cream together the margarine, butter, dark brown soft sugar and caster sugar. Beat in the eggs, peanut butter and vanilla. Combine the flour, bicarbonate of soda, salt and ground ginger, stir into the creamed mixture. Finally, stir in the oats and ginger. Drop heaped spoons of the batter onto ungreased baking trays.
Bake for 10 to 12 minutes in the preheated oven, until golden brown. Remove from the baking tray to cool on wire racks. Store in an airtight container when cool.