Prepare the Ingredients: Chop the chicken, onions, bell peppers, and tomatoes. Mince the garlic and ginger.
Cook the Aromatics: Heat oil in a pan. Sauté onions until golden. Add garlic, ginger, and green chilies. Cook for 1-2 minutes.
Add the Chicken and Spices: Add chicken and cook until white. Stir in cumin, coriander, turmeric, and red chili powder.
Simmer the Sauce: Add diced tomatoes and tomato puree. Cook for 5-7 minutes. Stir in bell peppers and cook for 5 minutes.
Finish and Serve: Sprinkle garam masala and garnish with cilantro. Serve hot with rice or naan.