Pre-heat your oven to 190° (or 170°c for a fan assisted oven or Gas Mark 5) and grease a couple of baking sheets. Set aside.
In a large bowl, sift the flour. Add the butter and rub together with your fingers until it resembles breadcrumbs.
Add the sugar and egg to the mixture. Add the milk a spoonful at a time, mixing together to create a thick, sticky dough - you may not need all the milk.
Add the orange extract and the mixed dried fruit. Mix until the dried fruit is evenly dispersed through the dough.
Place a tablespoon sized amount of dough onto your pre-greased baking sheets. Repeat with the rest of the dough, leaving space between each ball. Don't be concerned with making them neat - the rougher the balls are, the more rock-like your buns will appear.
Bake in your pre-heated oven for around 15 minutes until they have a nice golden colour.
Allow to cool a little on the baking sheets before transferring to a wire rack to cool completely. Although rock buns are best enjoyed when still a little warm from the oven!
You can substitute the orange extract for lemon extract or vanilla extract, although orange works nicely as it compliments the peel in the mixed dried fruit.