In a small bowl, mix together the yeast, sugar and water. Set aside for 5-10 minutes until frothy.

Sift the flour and salt into a separate large bowl. Make a well in the middle of the flour, then add the yeast mixture.

With a fork, mix until everything is well incorporated and you have a shaggy, wet, and sticky dough.

Cover and leave to rise somewhere warm for 1-1½ hours, or until doubled in size.

Once risen, knock back the dough. With your fingertips or a fork, lift the edge of the dough furthest from you and pull it over the centre of the bowl.

Turn the bowl by 90 degrees and repeat. Repeat six more times and re-form the dough into a ball.

Cover and leave to prove for a second time for 1-1½ hours, or until doubled in size.

Tip out the dough onto a lightly floured work surface, scraping down the bowl's sides.

Dust the top lightly with flour, then divide it into two or four equal-sized pieces.

Using well-floured hands, shape each into a ball, pinching any ends together.

Place each ball (pinched side as the base) on your surface.

Place the sides of your hands around the ball and firmly press them against its base while lifting and rotating it, repeating until a smooth, taut surface forms.

Repeat with the remaining three pieces.

Line a large baking surface with parchment and dust with flour.

Place the dough balls onto the baking sheet, spaced well apart, and prove, uncovered, somewhere warm for 35-45 minutes until doubled in size.

Preheat the oven to 250°C fan (475°F) or as hot as it will go.

Using your fingertips, flatten each dough ball out into a circle about 12-15 cm (5-6 inches) in diameter, taking care not to knock all the bubbles out.

Make a criss-cross pattern over the top with a lightly floured dough scraper or a palette knife.

If using, sprinkle the nigella or sesame seeds over the top.

With your hand, sprinkle some water over the top.

Bake in the oven for 10-12 minutes, or until light brown, puffed up and hollow-sounding when tapped on the base.

Remove from the oven and transfer to a wire rack to cool a little.

Serve warm.