Grandma used to bake these biscuits for us as kids. She said the recipe was brought into New Zealand by the Americans during WW2.
6 oz (150g) flour
4 oz (125g) butter
2 oz (60g) sugar
3 oz (100g) chopped dark chocolate
1 teaspoon baking powder
2 tablespoons condensed milk
pinch of salt

Cream butter and sugar, add condensed milk and chopped chocolate. Sift in flour,
baking powder and salt and mix well.
Roll out and cut Into rounds. Bake at 350 deg F
(160 deg C) for 15 minutes.