Preheat the oven to 180C/350F/gas mark 4
Use a 1.4kg/3 lb loaf tin.
Grease the loaf tin. Line the base with greaseproof paper; grease the paper. Cream the butter, rind and sugar in small bowl until light and fluffy. Add the sour cream and mix well. Transfer to a large bowl. Stir in the sifted dry ingredients, milk, courgettes and pecans. Spread into the prepared tin. Bake for about 45 minutes, Stand ten minutes before turning on to wire rack to cool. Spread the cold cake with icing.
Orange icing: Beat the butter and rind in a small bowl with a wooden spoon until smooth. Gradually beat in the sifted icing sugar and juice. Beat until spreadable.
