Chick pea and cauliflower curry

• 1 cauliflower, separated into florets 
• 800g potatoes, roughly chopped 
• 2 tbsp olive oil
 
• 2 tbsp butter
 
• 2 garlic cloves, thinly sliced
 
• 1 onion, thinly sliced 
• 1 long green chilli 
• 1 tsp ground turmeric
 
• 1 tsp ground cumin
 
• 1 tsp ground coriander
 
• 1 tsp mustard seeds
 
• 1 tsp ground ginger
 
• 1 tsp curry powder or garam masala  
• 1 x 400g tin chickpeas, drained
 
• 250g baby spinach leaves
 
• Yoghurt and lime juice, to serve 

1. Cook the cauliflower in salted boiling water for 5 minutes, then drain, reserving about 150ml cooking water.

2. Cook the potatoes in salted boiling water for 10 minutes, then drain.

3. Heat the olive oil and butter in a large frying pan or saucepan over a low heat and sauté the garlic, onion and chilli until softened. Stir in all the spices, season, and cook for a few minutes. Add the cauliflower, potatoes and reserved cooking water, then simmer over a low heat for 10 minutes. Add the chickpeas and spinach. Cook, stirring, until the spinach wilts. Transfer to a serving bowl and serve with a dollop of yoghurt and a good squeeze of lime juice.