Why This Recipe Works
When developing our best focaccia recipe, we noticed that a couple of recipes from southern Italy added riced potato to the dough. We found that it produced a bread with moistness, a pleasantly soft texture, and a high rise, but the dough still needed more lift. We knew that sponges (relatively thin mixtures of yeast, water, and flour that are allowed to ferment briefly) are often used to lend flavor and create air holes in bread. So we tried a quick sponge with our working focaccia recipe, stirring the yeast, half the water, and a small portion of the flour together in a small bowl, then covering the bowl with plastic wrap and letting the sponge rest for 30 minutes before adding the remaining ingredients. The fermentation of the sponge produced wonderfully large bubbles, and the result was a bread that rose very high and had a nice, light texture.