Preheat the oven to 230 ºC, 15 minutes before baking.
Sieve the flour into a large mixing bowl, stir in the salt, sugar and yeast. Using your fingertips, rub the fat into the flour until the mixture resembles fine breadcrumbs.
Make a well in the centre of the dry ingredients and add approximately 300 ml tepid boiled water.
Using a fork, mix well, then, using your hand, work together to form a firm dough. Turn dough onto a lightly floured surface and knead for about 10 minutes, or until smooth and elastic.
Lightly oil a clean bowl, place the dough in the bowl, then cover with a clean tea towel.
Leave in a warm place for approximately 1 hour, or until the dough has doubled in size.
Turn the dough onto a lightly floured surface and knock down. Using your knuckles, knead again, flattening and stretching the dough to remove any air bubbles.
When dough is smooth and elastic, cut off approximately a third. Shape the larger piece into a smooth round ball, then place on a lightly greased baking sheet.
Shape the other piece of dough into a smaller round ball. Brush the top of the larger piece with water, then place the smaller part on top. Press down firmly.
Dust your forefinger with a little flour, then carefully make an indent in the centre of the smaller round ball.
Cover the loaf with a clean tea towel and leave to rise in a warm place, away from draughts, for approximately 30 minutes or until the dough springs back when lightly pressed with the finger.
Brush the loaf with a little milk, then bake for 20 to 25 minutes, or until cooked (to test whether the loaf is ready, turn it upside down and tap lightly on the base - it should sound hollow).
Leave to cool on a wire rack, then serve with butter.