Heat the olive oil in a large nonstick skillet. Cook the onions over medium-low heat until a light golden brown, about 10 minutes, stirring occasionally. Stir in the chickpeas and curry powder and continue sautéing the onions until a deep golden brown, about 3 minutes.
Combine the yeast, sugar, and 1/4 cup warm water in a small mixing bowl and stir to mix. Let stand for 6 to 8 minutes: It should foam like a head of beer.
Prepare the sponge: Stir 2 tablespoons warm water into the yeast mixture. Stir in 1 cup flour or enough to obtain a moist but shapable dough. Roll the dough into a ball and drop it into a deep bowl filled with warm water. It will sink to the bottom. After 5 to 10 minutes, it will rise to the surface. The sponge is now activated and ready to use.
Transfer the sponge to a large mixing bowl. Stir in the remaining water, the 2 tablespoons honey, the salt, and the onion-chickpea mixture. Stir in the flour, one cup at a time. Add flour until the dough becomes too stiff to stir: It should be dry enough to come away from the sides of the bowl but soft enough to knead. Turn the dough out onto a lightly flouted work surface. Wash the bowl and lightly oil it with spray oil.
Knead the dough for 6 to 8 minutes, or until smooth and elastic. If the dough is too sticky to knead, work in a little more flour. Note: The dough can be mixed and kneaded in a heavy-duty mixer fitted with a dough hook or a large food processor fitted with a dough blade.
Return the dough to the oiled bowl and cover with plastic wrap. Place it in a warm, draft-free spot and let it rise for 1-1/2 to 2 hours, or until doubled in bulk. (The dough can be allowed to rise at lower temperatures--even in the refrigerator--but the rising time will be longer.)
Punch the dough down and cut in half. Pat each half into an 8-inch-long oval. Plump the ovals in the center and drop them, seam side down, into two 9-inch loaf pans greased with spray oil.
Cover the loaves with dish towels and let the dough rise again until doubled in bulk. Preheat the oven to 375° F. Brush the top of each loaf with beaten egg white or water and, using a sharp knife or razor blade, make a series of parallel diagonal slashes, 1/4 to 1/2 inch deep.
Bake the loaves for about 35 to 40 minutes, or until firm and nicely browned. The standard test for doneness is to tap the bottom of the loaf: If it sounds hollow, the bread is cooked. You can also test for doneness with an instant-read thermometer: The internal temperature should be about 190° F.
Let the breads cool for 5 minutes in the loaf pans, then turn them out onto a cake rack. Let cool slightly or completely. (Bread piping hot out of the oven is very hard to slice.)