Harissa soup with chickpeas

Ingredients

• 2 large_piece (700g) red capsicums (bell peppers)
• 1 tablespoon olive oil
• 3/4 teaspoon ground ginger
• 3/4 teaspoon ground cumin
• 1/2 teaspoon ground turmeric
• 1/2 teaspoon ground cinnamon
• 2 cloves garlic, chopped coarsely
• 4 long red chillies, chopped coarsely
• 1 red bird's-eye chilli, chopped coarsely
• 2 medium_piece (300g) tomatoes , chopped coarsely
• 1 1/2 cup (375ml) chicken stock
• 2 x 3cm (1¼-inch) strips lemon rind
• 400 grams (12½ ounces) canned chickpeas (garbanzo beans), drained, rinsed
• 1 teaspoon cumin seeds
• 1/3 cup (95g) greek-style yoghurt
• 1/2 teaspoon lemon rind, finely grated