In a large bowl, combine 600 g cubed chicken thighs, 3 tbsp plain yogurt, 1 tbsp ginger garlic paste, 2 tsp red chili powder, 0.5 tsp turmeric powder, 1 tsp garam masala, 0.5 tsp ground cumin, 1.5 tsp salt, 1 tbsp lemon juice, 0.5 tsp black pepper, 10 curry leaves (torn), and 0.25 tsp red food coloring if using. Mix well, cover, and marinate in the refrigerator for at least 30 minutes or up to 4 hours.