Preheat the oven to 350°F (175°C or Gas Mark 4).
Grease and flour two - 2 pound loaf pans (roughly 22.5 cm x 13 cm x 6 cm each).
Sift together the flour, baking soda, salt, cinnamon, ginger and nutmeg. Set aside.
Break up the bananas and mash with a fork.
Put the mashed bananas, white and brown sugar in the bowl of an electric mixer and mix together well.
Add the oil, eggs, sour cream or crème fraîche, vanilla and orange rind. Beat together thoroughly.
Add the sifted flour mixture and mix until just combined.
Stir in the chopped nuts.
Divide the batter between the two loaf pans. The batter will about half fill each pan.
Bake for 30 to 35 minutes until the top of the cake springs back when touched lightly and a skewer inserted in the centre of the cake comes out clean.
Remove the pans from the oven and cool on a wire rack for ten minutes before turning out to cool completely on a rack.
When the cake is completely cool, make the glaze by sifting together the icing sugar and the ginger.
Add water, a few teaspoons at a time, until a drizzle-able consistency is reached.
Pour or drizzle the glaze over the cakes and sprinkle with chopped nuts.
Allow the glaze to set before slicing.