Roughly chop the cod. Drain the prawns on kitchen paper. Peel and chop the sweet potatoes. Peel and chop the onion. Chop the tomatoes. Slice the green chilli (remove the seeds if you prefer it milder). Reserve a few chilli slices for garnish.

Heat a pan or a pot over a medium-high heat with a drizzle of oil. Once hot, add the sweet potatoes, onion and mustard seeds, and fry with a pinch of salt for 5 min. Add the tomatoes, green chilli (spicy!) and curry leaves, and fry for 2-3 min further.

Add the madras curry powder (spicy!), turmeric powder, ginger garlic paste and tomato paste and stir for 1-2 min. Add the measured water and chicken stock cube. Simmer for 15-18 min, covered, or until the sweet potatoes are tender.

Once tender, add the coconut milk, cod and prawns. Cook for a final 5 min or until the seafood is cooked through (don't overcook it!).

Divide the curry among bowls and season with a squeeze of lime juice. Garnish with the remaining green chilli slices (spicy!).