Preheat oven to 350 degrees F. Grease and flour an 8 ½ by 4 ½ inch metal loaf pan or line inside with nonstick foil.
In a large mixing bowl, combine flour, both sugars, salt, baking soda, ginger and nutmeg. Stir thoroughly.
Make a deep well in the center of the flour mixture and add the yogurt, oil, lemon zest, lemon juice, vanilla and eggs.
With a large mixing spoon (I like using a heavy duty silicone scraper), mix the liquid ingredients together in the well, then mix the dry ingredients into the liquid and continue stirring until blended. Do not over-beat.
Transfer the batter to the pan and bake on center rack for about 1 hour and 10 minutes. Let cool completely in the pan.
When cool, prepare icing by mixing all icing ingredients together until smooth. Drizzle over cake and let set.