1 For the karahi curry sauce: heat the oil in a pan, add the onions, garlic and chillies and fry over a medium heat for approximately 10 minutes or until the onions are caramelised. 2  Add the cumin, coriander, turmeric, salt and garam masala and stir.3  Mix in the ginger and pureed tomatoes and cook for 1 minute, stirring. Remove from the heat and keep warm. 2  For the chicken: heat the oil in a wok or heavy-based frying pan and add the chicken. 3  Stir-fry over a medium heat for 8-10 minutes or until the chicken is golden brown all over. 4  Stir in the karahi curry sauce and simmer for 2-3 minutes. 5  Garnish with cilantro leaves.