Pre-heat oven to 180°c / 350°f / Gas Mark 4. Grease and flour cake tin. Put the flour, baking powder, cinnamon, ginger and sugar into mixing bowl and stir together. Pour in the oil, eggs and orange juice and beat well until smooth.
Add the carrots and orange zest and fold in gently. Pour mixture into prepared cake tin.. Place the tin in the centre of the oven and bake for 60-70 minutes or until the cake shrinks away from the side of the tin.
Leave to cool in the tin for approximately 30 minutes. Turn out onto a wire rack and leave to cool completely. Store in an airtight container.