Preheat the oven to 250°C/475°F/Gas Mark 5
Prepare the orange butter first. Cream the butter with the orange zest, add the sieved icing sugar and beat togeether until light and fluffy.
Sieve the flour, baking powder, and salt into a large bowl. Add the castor sugar.
Cut the chilled butter into cubes and rub into the dry ingredients.
Add in the dried cranberries
Add the milk and bring the ingredients together into a soft dough.
Turn dough out onto floured work surface. Handling it as little as possible roll into a rectangle about 2cm/¾ in high and about 35 x 23cm/14x 9 in.
Spread the orange butter gently over the top surface of the dough. Gently roll up the dough like a swiss roll.
Cut the rolled scone dough into about 14 slices.
Place the scones cut side down in the tin. Brush with the milk and sprinkle with the granulated sugar.
Put the scones in the oven for 5 minutes then turn down the heat to 230°C/450°F/Gas Mark 8. Bake for a further 10 minutes.