Sweet Olive Oil Bread (Pompe à l'Huile)

Pompe a l'huile, a sweet olive oil bread that's a cross between a brioche and a focaccia, is at the center of the spiritual food traditions that make a Christmas in Provence like none other in the world. This version uses a liquid starter called a poolish—a mixture of water, a little flour, usually some sugar, and yeast that's allowed to ferment—to give the bread a unique flavor.