1.Preheat oven to 230°C. Grease 20cm round sandwich cake pan. Sift flour, ginger and sugar into medium bowl, rub in butter, add berries and sour cream. Stir in enough milk to mix to a soft, sticky dough.
2.Turn dough onto floured surface, knead until smooth. Press dough out to 2cm thickness, cut into 5cm rounds, place into prepared pan.
3.Bake about 15 minutes.
4.Meanwhile, to make custard cream, beat cream, custard and icing sugar in small bowl with electric mixer until soft peaks form.
5.Serve scones with custard cream, dusted with sifted icing sugar, if desired.