Preheat the oven to 200°C/400°F/Gas mark 6
Cream together the yoghurt, sugar, butter, sour cream and lemon peel. Sift together the flour, soda, baking powder and salt. Fold into the creamed mixture and blend well. Fold in the blueberries. (If using frozen - defrost first)
Drop by tablespoonfuls onto a greased baking sheet. Bake for 15 minutes or until lightly browned.
Stir together the glaze ingredients. Drizzle over the warm cookies. Cool on a wire rack.
