Soak the Dried Chickpeas in cold water overnight (or for at least 8 hours). Rinse and drain before cooking. Rinse the Brown Lentils and set aside.
Trim and cut the Lamb Shoulder into bite-sized pieces, then season lightly with Fine Salt and freshly ground Black Pepper.
Heat the Olive Oil in a large heavy pot over medium-high heat. Brown the lamb in batches until nicely seared, then remove and set aside.
Reduce heat to medium and add the chopped Onion and diced Celery to the same pot; sauté until soft and translucent, about 6–8 minutes.
Stir in the spices—Ground Ginger, Ground Turmeric and Ground Cinnamon—and lightly toast for 30 seconds, then add the Saffron Threads (crush them between your fingers) and the Tomato Paste; cook and stir for 2 minutes to deepen the flavors.
Add the Canned Crushed Tomatoes and return the browned lamb to the pot. Pour in enough Water to cover the ingredients by about 2 inches (roughly 8–10 cups, adjust as needed). Add the soaked Dried Chickpeas and the rinsed Brown Lentils. Bring to a simmer, then reduce heat to low and cook gently, partially covered, until the chickpeas and lamb are tender, about 1 to 1½ hours (check and add more water if needed).
When the legumes are nearly tender, break the Fine Vermicelli into short pieces and stir into the soup; simmer for 6–10 minutes until the vermicelli is cooked.
Make a slurry by whisking the All-Purpose Flour with a cup of cool Water until smooth. Temper the slurry by adding a ladle of hot broth to it, then slowly whisk the tempered slurry back into the pot to thicken the harira slightly. Simmer 3–5 minutes, stirring, until the soup has a silky, thickened consistency.
Stir in a generous handful of chopped Flat-Leaf Parsley and chopped Cilantro. Taste and adjust seasoning with additional Fine Salt and Black Pepper as needed.
Turn off the heat and finish with a squeeze of Lemon to brighten the flavors. Let the soup rest a few minutes before serving; serve hot with extra lemon wedges on the side.
