Preheat the oven to 225ºC/440ºF/gas mark 7

Grease & line a baking sheet with parchment paper

Into a large mixing bowl, sift together the flour, cream of tartar and salt

Rub in the cubes of butter

Stir in the sugar

Make a well in the centre and pour in the buttermilk

Bring the mixture together until it forms a ragged ball of dough. Don't over mix

Fold in the chopped hazelnuts and chocolate chips

Turn the mixture out on to a well-floured work surface and flatten the dough to about 5cm high

Use a circular cutter to form the scones. Bring together the remaining bits of dough to form a solid ball. Gently flatten again so that you can cut out more circles

Put the scones on the prepared baking sheet and brush the top of each with a little milk or egg-wash

Bake for 12-15 minutes or until the tops are a lovely golden brown

Allow to cool completely on a wire rack