Moroccan fish tagine with coriander couscous

Ingredients

• 1 red onion, finely chopped

• 2 garlic cloves, finely chopped

• 2 tbsp groundnut oil

• 1 tsp whole cumin seeds

• 1 tsp ginger

• 1 cinnamon stick

• 1 preserved lemon or normal lemon, chopped

• 12 green olives, stoned and roughly chopped

• 1 tbsp homemade harrissa (see below)

• 125ml/4fl oz white wine

• 200ml/7fl oz fish stock

• 1 pinch of saffron

• 500g/1lb 2oz mixed firm fish, such as monkfish, gurnard, mackerel

• 200g/7oz mussels

• 100g/3½oz cherry tomatoes

• couscous and coriander to serve

For the home-made harrissa

• 3 fresh red chillies, roughly chopped

• 3 garlic cloves, finely chopped

• 1-2 lemons, juice only

• 4 tbsp olive oil

• salt

• freshly ground black pepper