How to make
Dissolve the yeast with the sugar and a little flour in the warm water, leave to bubble.
In a separate container, sift the flour with the salt, make a well and pour the effervescent yeast in it.
Knead a soft, stretchy dough, put it in a floured bowl to rise.
Once the dough is nearly doubled in volume, knead it again, form into a ball and put it in the oiled and floured oven dish in which you'll be baking, to rise again.
Once doubled in volume again and right before you put it to bake, make a few cuts on it with a sharp knife. Bake in a preheated 390°F (200 °C) oven about 50 min, with a container of boiling water at the bottom of the oven.
If you don't like the crunchy crust that forms you can smear it with a little yoghurt before putting it to bake.