Combine together ginger, garlic, turmeric, coriander, garam masala, fennel, red chili powder (if using), paprika, black pepper, yogurt, 2 teaspoon lemon juice, fenugreek leaves, oil, and enough salt in a bowl to form a smooth paste. Marinate chicken for at least 30 minutes in the refrigerator. Place chicken in oven and bake for 30 minutes. Slice into small pieces.