Measure out the sugar; remove 1 teaspoon of the sugar and place it with the yeast in a small bowl. Add the warm water and let the yeast activate for 15 minutes until a thick head of foam forms.

Place the flour in a large mixing bowl with the salt, the orange zest, and the rest of the sugar. Using your hands, blend the dry ingredients together, breaking up the clumps of orange zest until the zest is evenly distributed in the flour. Make a well in the center.

Once the yeast has been activated, pour the mixture into the well in the flour. Add the olive oil and the orange flower water. Using a wooden spoon, stir until the ingredients are well blended and a dough pulls together. If the dough is too loose and wet, stir in another 1 - 2 tablespoons of flour.

Scrape the dough out onto a floured work surface and knead for about 5 minutes until the dough is smooth. Place this dough into a lightly oiled bowl, turning the dough to barely coat with the oil, cover the bowl with plastic wrap and a clean kitchen towel and let rest for 2 hours; it will have risen but not doubled in size.

Knead the dough on a floured work surface for just a couple of minutes until smooth. Roll the dough out to a 9 to 9 ½ -inch (23- to 24-cm) circle ½ -inch (1-cm) thick. Carefully lift the circle of dough and place on a parchment-lined baking sheet; reshape if necessary. Make 8 or 10 evenly spaced slashes in the dough from about an inch from the center and stopping about an inch from the outer edge. Cover loosely with a piece of plastic wrap and the clean kitchen towel and let rest for 1 hour. It will rise just slightly.

Preheat the oven to 375°F (190°C). Brush the pompe à l’huile all over with a light layer of olive oil then place in the preheated oven and bake for about 20 minutes until risen and a deep golden all over.

Remove from the oven and slide off the baking sheet onto a cooling rack and immediately brush all over with a light layer of olive oil. Allow to cool until warm.

Dust with powdered sugar and serve, passing around the galette and letting each guest rip off their own wedge.