Traditional Mexican bread from Jalisco, commonly used for "tortas ahogadas".
Mix all the ingredients for the dough starter in a bowl, it will end being a runny dough. cover the dough starter with a clean cloth and let it rise until it doubles. For the "birote" dough mix the flour, sugar, salt and the dough starter and knead the dough, add water. Stop kneading until you get a soft and elastic dough; it takes some time to get to this stage and I highly recommend adding water at different stages and not all at once. Let the dough rise until it doubles. Weigh 150 gm portions, and shape the birote. Use this video for guidance http://www.youtube.com/watch?v=Jlzgy7bvJRs&feature=related. Once shaped let them rise until they double. Before baking, cut the center of the Birote using a cutter, --use a sharp cutter to avoid deflating the birote. Then, apply the glaze and bake at 240ºC / 450ºF for about 20 minutes.
http://en.wikipedia.org/wiki/Bread_improver, the bread improver is not really necessary but really improves the texture and shelf life of the bread. this recipe is commonly used to prepare "tortas ahogadas" but could be filled with many ingredients or cut into slices to prepare "tapas" or bread puddings like "capirotada"