A recipe from Hidden Spirit

Title: Caramel Shortbread
Serves: Depends how big you cut the squares and also if you want to share Seriously though, it makes about 25 decent size squares

Biscuit Base
8oz plain flour
6oz margarine (got to be suitable for home baking or it won't turn out too great)
30oz caster sugar

2oz margarine
2oz soft brown sugar
Large tin of condensed milk

8oz milk chocolate

Rub the margarine and flour together in a bowl until you have a mix which is similar to breadcrumbs. Stir in the sugar. Spread the mixture evenly into a 9" (23cm) square tin which has been lined with baking parchment. Bake in a pre-heated oven at 170C/340F (160C/320F if fan assisted) for approximately 35 minutes until it is golden brown. Allow the base to cool.
Heat the filling ingredients together in a pot, making sure that you stir it constantly (otherwise it will stick!) until it begins to simmer. Continue stitting until it thickens (which it should do in a few minutes). Spread the filling evenly over the base and again allow to cool.
Melt the chocolate so that you can spread it over the filling.
When it has cooled and set, cut up into squares or rectangles with a sharp knife.