They put a dough on a leaf of cabbage when baking not to get the bottom of the dough stuck inside the oven. 

 As it contais a lot of water, it has a chewy texture even when toasted.

It's been popular and common bread among the people because of the low cost. 

"Pão de Áqua" 

(Bread of water) 

The flour used for making this bread can contain up to 90% of water.

Other ingredients are only salt and yeast and it makes a fresh and really soft bread.