Place the flour, cream of tartar and bicarbonate of soda into a large bowl and stir well to combine. Add the butter and rub in with your fingertips until it resembles breadcrumbs, before stirring in the sugar.
Break the eggs into a measuring jug, beat and add the buttermilk until the volume reaches 500ml, beating until well combined. Set aside 3 tbsp of the mixture for brushing on top of the scones.
Add the egg mixture slowly into the scone crumbs and mix using a round bladed knife. Bring the mixture into a ball of dough, finishing it off with your hands until it becomes a smooth ball of dough. If you need to add more liquid, add it from the reserved egg mixture removed initially. The dough should not be sticky as this will result in scones which will be too soft and not hold their shape in the oven.
On a lightly floured surface, roll the dough to the thickness of approximately 2″ high. Insert the frozen raspberries into one half of the dough and flip the other half over to cover the raspberries. Finally roll the dough out to approximately 1.5″ thick and stamp out using a fluted cutter.
Place the scones onto the baking tray, keeping them not too close, using a second tray if necessary.
Tip: instead of rubbing the butter in with your fingertips, this may be done in the food processor. Just place the flour, butter, bicarbonate of soda, cream of tartar and the sugar into the food processor and pulse until even sized crumbs are created.
