1. For the chicken, place the chicken legs into a shallow dish and sprinkle over the turmeric and salt. Cover and chill in the fridge overnight to marinate.
2. Remove the marinated chicken from the fridge half an hour before you are ready to cook it.
3. Meanwhile, for the spice paste, blend all of the spice paste ingredients in a food processor until smooth.
4. To cook the chicken, heat a casserole dish over a high heat, add three tablespoons of the oil and, when it is smoking, add the chicken. Fry the chicken for 4-6 minutes, or until golden-brown on all sides.
5. Remove the chicken from the casserole dish and set aside to drain on a plate lined with kitchen paper.
6. Using the casserole dish again, add the remaining vegetable oil, the onion, spice paste and curry powder and stir-fry for 2-3 minutes, or until fragrant.
7. Add the chicken, then the tamarind paste, coconut milk, lime leaves, potatoes, salt and sugar
8. Put it in the oven at 180C for 45-60 minutes, or until the chicken is tender and cooked through.
9. Add the lime juice and stir well.
10. To serve, spoon the curry into four serving bowls. Sprinkle with the crispy shallots, mint leaves, red chillies and cucumber slices. Serve the steamed rice alongside.
