Heat a small frying pan over a high heat for 2 to 2.5 minutes. Once hot, add the coriander, cumin, cardamom and mustard seeds. Toast for 30 seconds, until they start to release their aromas, tossing gently to move them around. Be careful that they don’t burn. Transfer the toasted seeds to a pestle and mortar and let them cool for 2 minutes, then grind for 30 seconds.
Heat the olive oil in a large saucepan or casserole over a medium heat. Add the onion and cook for 3 minutes, stirring frequently. Then add the spices, garlic, ginger and chilli, and cook another 3 minutes, stirring frequently.
Increase the heat to high and add the turmeric, coconut milk, water, crumbled stock cube or pot and salt. Stir continuously until just starting to boil.
Add the potatoes, carrots and cauliflower, cover with a lid and simmer for 15 minutes, stirring occasionally. Then add the green beans and frozen peas or petit pois, cover and simmer for a further 5 minutes.
Serve, garnished with chopped coriander leaves and your favourite Indian sides.