To make the pastry cases, Place the flour in a mixing bowl and rub in the butter until the mixture resembles fine breadcrumbs. Add enough cold water to mix to a dough.
Wrap and allow the dough to relax in a cool place or the refrigerator for about 15 minutes. Roll out the pastry and use to line the pastry cases. To avoid over rolling I tend to divide the pastry up into smaller pieces so I don't have to keep re-rolling.
Prick the base of the tarts with a fork. Line each case with a piece of parchment and fill with baking beans. Chill for at least 30 minutes or pop into the freezer for 15 minutes.
Preheat the oven to 200℃ /180℃ fan/gas mark 6. Place the pastry cases on a baking tray and bake blind for 10 minutes. Remove the baking beans and parchment and return to the oven for another 10 minutes or until pale golden.
Meanwhile heat the oil in a frying pan and sauté the onion for 1-2 minutes. Then add the beetroot and cook until soft, stirring frequently – about 10 minutes.
Once the pastry cases are baked, reduce the oven temperature to 180℃ /160℃ fan/gas mark 4. Divide the beetroot mixture equally among the pastry cases.
Beat the eggs and milk together with a fork and season with salt, pepper and nutmeg. Pour into the pastry cases. Top with a slice of goats cheese. Return to the oven and bake for 15 to 20 minutes until the filling is just set.