Homemade tomato sauce - Good Food Middle East

Ingredients

• 1 tbsp olive oil
• 2 onions, chopped
• 1 thumb-size piece fresh root ginger, finely chopped or grated
• 2 garlic cloves, chopped
• 1 red chilli, deseeded and finely chopped
• 800g tomatoes, briefly whizzed in a food processor or finely chopped
• 100g dark brown sugar
• 100ml red wine vinegar
• 2 tbsp tomato purée
• coriander seeds