Aunty Ruth's Rock Buns

My Great Aunty Ruth is the greatest. This is one of my favourite biscuit recipes of all time. Simple and tasty, the name makes them sound hard but they are actually melt-in-you-mouth buttery. At 89 years of age, this recipe has been around for a long time, it was passed down from her mother. No one can make them quite as good as her but we always try.
 

Ingredients:
225g Self-raising flour
110g Salted butter
1 egg
80g Sultanas
110g white Sugar plus more for dusting
Tablespoon of milk

Sift flour into a bowl, rub in butter. Mix in sugar and then sultanas. Beat eggs and a very small amount of milk (probably only about a tablespoon) together then mix into the dry ingredients. Add more milk if necessary to make a dough. Place spoonfuls on greaseproof pater on a baking tray. Sprinkle with plain white sugar. Put in the freezer for a few minutes. Bake in a moderate oven (180 degrees if fan forced, 220 if conventional) for about 8 minutes. Cook until lightly golden.

Enjoy with a cup of tea.