Soak the garbanzo beans overnight in 4 quarts / 3. 8 liters of water with a pinch of baking soda. The next day, drain and rinse the beans.
Add them to a large pot with 2 of the onions (peeled and whole), 1 tablespoon (15 ml / 0.5 fl oz) of the olive oil, and 1 teaspoon of salt.
Cover with fresh water by at least 3 inches.
Bring to a boil, then reduce the heat to a simmer.
Cook, partially covered, until the beans are perfectly tender, about 1. 5 to 2 hours.
While the beans cook, prepare the vegetables.
Peel and cut the remaining onion into 1-inch chunks.
Peel the potatoes and cut them into large cubes. Core the cabbage and cut it into large wedges. Trim the leeks, slice them in half lengthwise (leaving the base intact), and rinse thoroughly.
Peel the carrots and cut them into 2-inch lengths.
Place all the prepared vegetables in a separate large pot.
Add 8 to 10 cups (2400 ml) / 2 to 2. 4 liters of water—just enough to cover them—and 2 teaspoons (10 ml / 0.3 fl oz) of salt.
Bring to a boil, then reduce heat and cook for 30 to 40 minutes, until all vegetables are fork-tender.
To make the dumpling batter, whisk together the egg, water, vegetable oil, salt, paprika, and saffron in a medium bowl.
In a separate bowl, sift together the whole wheat flour and baking powder, then stir the dry into the wet mixture until just combined.
Do not overmix.
Once the beans and vegetables are cooked, carefully drain both, reserving all the cooking liquid.
Discard the 2 whole onions from the bean pot.
Keep the beans and vegetables in their separate pots, covered, in a warm oven to prevent them from getting cold.
Combine 5 cups (1200 ml) of the reserved vegetable broth with all of the reserved garbanzo broth in a saucepan.
Bring to a simmer and season to taste with salt and pepper.
Add the broken fideo noodles and cook for 6 to 7 minutes, or until tender. This is your soup course.
While the soup simmers, bring a medium pot of salted water to a boil for the dumplings.
Drop the batter by scant teaspoonfuls into the boiling water.
Cover the pot, reduce the heat, and let them gently cook for 20 minutes. They will be light and cooked through.
To serve, ladle the hot fideo soup into bowls for the first course. For the main course, arrange the warm garbanzos in the center of a large platter with the vegetables surrounding them.
Drizzle everything generously with the remaining olive oil and a sprinkle of salt and pepper. Use a slotted spoon to remove the dumplings from their water and place them on the platter.
Serve immediately.
Don't skimp on salting the cooking water for both the beans and vegetables. This builds a flavorful foundation for your final soup.
