2) In a separate bowl, add the matzo meal and sift in the baking powder. Mix together, then fold into the egg mixture. Cover with cling film, pressed tightly against the batter and refrigerate for at least 1 hour, or overnight.
3) Moisten your hands lightly with water and form the matzo mixture into 24 walnut-sized balls. Carefully drop the matzo balls into the water or broth. Reduce the heat to medium and partially cover. Simmer gently until the matzo balls are cooked through, about 40 minutes. Using a skimmer or slotted spoon, transfer the matzo balls to a large bowl of cold water.
For the soup:
1) Bring the chicken pieces and stock to the boil in a large pan over a medium-high heat, skimming off the foam that rises to the surface. Reduce the heat to medium-low. Simmer, partially covered, until the chicken is tender, about 25 to 30 minutes.
2) Remove the chicken from the soup. Remove and discard the skin, shred the meat into bite-sized pieces, and reserve the meat until service. Return the remaining bones back to the broth and simmer for 15 to 20 minutes more to further develop the soup's flavour.
3) Whilst the soup is simmering, make the sofrito. Heat the oil in a medium skillet over a medium heat. Add the onion, tomatoes, red and green peppers, coriander, garlic and saffron. Cook, stirring occasionally, until the vegetables in the sofrito are tender, but not browned, about 8 minutes. Add the hot sauce, if using. Set the sofrito aside.
4) When ready to serve, strain the soup and discard the bones. Return the soup to the pan and stir in the sofrito and chicken pieces. Add the matzo balls and simmer until the matzo balls are heated through, about 5 minutes.
5) Ladle the soup, along with sofrito, chicken and matzo balls, into bowls and serve hot, with an optional drizzle of the additional melted chicken fat (schmaltz).
Notes: The soup and matzo balls can be prepared up to 2 days ahead, covered and refrigerated. Reheat before serving.
If you are concerned that the oils or other ingredients in these recipes are suitable for Passover, use non-dairy substitutes or ingredients that are certified kosher for Passover.