Heat the oil in a large braiser or pot set over medium-high heat.
Dry the lamb with paper towel and sprinkle with 1 1/4 teaspoons of the salt. Dredge each piece in the flour and then shake off the excess. Add the lamb to the pan and sear on all sides until deep golden brown, 8 to 10 minutes. Transfer the lamb to a plate.
Add the garlic, celery, carrots and onions to the pan and season with the remaining 1/2 teaspoon salt. Cook until the vegetables begin to brown and soften, about 3 minutes.
Add the tomato paste and berbere spice and cook, stirring often, about 2 minutes.
De-glaze with the wine and bring to a boil, then reduce the heat to medium and simmer for 3 minutes. Stir in the broth, bay leaf, and cinnamon stick.
Nestle the lamb back in the pan with the juices and cover with a lid. Reduce to low heat and cook until the lamb is soft and tender, about 2 hours.
10 minutes before it’s ready, add the swiss chard and stir until wilted.
For the couscous, peel the zest from the orange, then juice the orange into a 1 cup measure. Fill the rest of the cup with the chicken stock. Put the chicken stock/orange juice mix into a pot with the peel and bring to a boil.
Turn off heat. Add the couscous, salt, and pepper and cover for 10 minutes.
Once ready, remove orange peel and fluff with a fork.
Add chopped coriander and fluff again.