To make the sponge: Combine all the ingredients and mix until smooth. Cover the sponge, and let it sit for 1 to 2 hours, or until it's very bubbly., To make the dough: Mix the salt into the sponge. Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. Gradually incorporate the bread flour, either by hand or stand mixer, until a shaggy dough forms., Knead the dough until it's smooth and somewhat stiff., Knead in the cooked quinoa, pecans, and dates until they're thoroughly incorporated into the dough; at this point the dough will have slackened, but shouldn't be too sticky to handle., Place the dough in a lightly greased bowl, cover, and set aside to rise until it's just about doubled in size, about 1 1/2 to 2 hours., Gently deflate the dough on a lightly floured work surface, divide it in half, and shape each half into a round (boule)., Place the boules on a cornmeal-sprinkled or parchment-lined baking sheet, cover, and let rise until not quite doubled in size, 45 minutes to 1 hour., During the final 20 minutes of rising, preheat the oven to 425°F., Bake the loaves for 15 minutes at 425°F, then reduce the oven heat to 375°F and bake for an additional 20 to 25 minutes, or until a digital thermometer inserted in the center of the loaves registers 200°F., Remove the loaves from the oven and transfer them to a rack to cool completely., Store, well wrapped, at room temperature for several days; freeze for longer storage.