Aubergine and chestnut tagine with couscous

Ingredients

• 1 tbsp ground coriander
• 2 tsp ground turmeric
• 1 tbsp ground cinnamon
• 3 tbsp olive oil
• 1 red onion, finely chopped
• 1 red chilli, finely chopped
• 2 garlic cloves, crushed
• 50g dates, finely chopped
• 2cm piece fresh ginger, grated
• 500g (about 2 small) aubergines, cut into 2cm cubes
• 600g pumpkin or squash, deseeded and cut into 3cm cubes
• 200g pack cooked, peeled chestnuts
• 2 x 400g cans good plum tomatoes
• Handful each chopped fresh mint and coriander, plus extra coriander to garnish
• Juice of 2 lemons
• 450g couscous
• 2 tbsp olive oil
• 5 shallots, sliced
• Handful each finely chopped fresh coriander and parsley