Preheat the oven to 180°C/350°F/Gas mark 4
Sift the flour with the salt and baking powder, set aside. Cream together the butter; sugar, sour cream, vanilla and dry ingredients. Mix well.
Drop by teaspoonfuls on an ungreased cookie sheet. Bake for 12 minutes. Cool. Break nuts into pieces and place on top of cookies, spoon icing over the top.
For the icing, mix the brown sugar and cream in a small saucepan. Bring to a boil, stirring constantly. Boil 2 minutes. Remove from heat and add the icing sugar/confectioner's sugar. Beat until smooth. Add extra cream if too thick. Spoon over the cooled cookies.
