Baked onion bhajis

Name: Baked onion bhajis
Prep time: 30 min
Cook time: 25 min
Total time: 55 min
Cuisine: Indian
Ingredients: 3 large (about 600g) onions; 1 tsp fine sea salt; 1 tsp cumin seeds; 2½cm piece ginger cut into matchsticks; ¼ tsp ground turmeric; ¾ tsp ground coriander; small bunch coriander finely chopped to make 3 tbsp; 2 green bird’s-eye chillies finely chopped; ¼ tsp kashmiri chilli powder (see cook's notes below); 100g gram flour; 1½ tbsp rapeseed oil; chutney or raita to serve