Preparation

• 1 On a hot grill or under a broiler, roast
  peppers until charred on all sides. Let cool,
  peel off skin and discard seeds. Slice roasted
  peppers into strips and toss together with
  harissa in a small bowl. Set aside.
  2 In a large pot, heat olive oil over medium-­
  high heat. Add onions and celery, and cook
  for 10 minutes. Stir in garlic, cumin seeds and
  smoked paprika, and cook for 1 minute.
  3 Add stock to the pot along with thyme,
  chickpeas, sweet potato and tahini paste.
  4 Bring to a boil, then cover and simmer over
  low heat for 25 minutes.
  5 Ladle soup into four bowls and garnish with
  harissa roasted peppers and a drizzle of kefir
  or yogurt.