Heat 1 tablespoon oil in a frying pan over medium high heat. Add chicken. Sprinkle with ground fenugreek and 1 teaspoon garam masala. Season with salt and pepper. Saute, stirring occasionally, for 6-10 minutes or until the chicken is cooked. Set aside.
Meanwhile, heat 1 tablespoon oil in a large saucepan over medium-high heat. Add bay leaves and onions, and sauté, stirring occasionally, for 2-3 minutes or until soft and translucent. Add ginger, garlic, ground cumin, 1 teaspoon garam masala, red chilli powder, butter and lemon juice. Saute, stirring, for 2 minutes.
Add tomato paste, and cook, stirring, for a minute. Add cream, yogurt and milk. Bring to the boil. Reduce heat, and simmer for 3-4 mins.
Stir cooked chicken in the sauce. Add ground cashew nuts, if using. Cook for another 3-4 minutes. Remove from heat. Garnish with coriander leaves.