In a large mixing bowl, combine the sourdough starter, warm water, and sugar. Stir until the sugar is dissolved.

Gradually add the flour and salt, mixing until a shaggy dough forms.

Turn the dough out onto a lightly floured surface and knead for about 10 minutes, until smooth and elastic.

Place the dough in a greased bowl, cover with a damp cloth or plastic wrap, and let it rise in a warm place for about 4-6 hours, or until it has doubled in size.

After the dough has risen, gently punch it down to release the air. Shape it into a round loaf and place it on a parchment-lined baking sheet.

Cover it again and let it rise for another 1-2 hours.

Preheat the oven to 450°F.

Once the dough has risen again, use a sharp knife to make a few slashes on the top of the loaf.

Bake the bread in the preheated oven for 25-30 minutes, or until the crust is golden brown and the loaf sounds hollow when tapped on the bottom.

Remove from the oven and let it cool on a wire rack before slicing.