1. Heat the vegetable oil in a large pan over medium heat. Add the finely chopped onion and sauté until golden brown, about 5 minutes.
2. Add the minced garlic and grated ginger, cooking for an additional minute until fragrant.
3. Stir in the ground cumin, coriander, turmeric, garam masala, and chili powder. Cook for another minute to let the spices bloom, stirring constantly to prevent burning.
4. Add the diced tomatoes, including their juices, and bring to a simmer. Let this cook for about 5 minutes, until the tomatoes break down slightly.
5. Pour in the coconut milk and stir well to combine. Bring the mixture to a gentle simmer.
6. Add the chicken pieces to the pan, ensuring they are well-coated with the sauce. Cover and cook over low heat for 15-20 minutes, or until the chicken is cooked through.
7. Season with salt to taste. Garnish with fresh cilantro before serving.

As you cook, remember my mom’s kitchen rule: taste as you go. Adjust the spices to suit your family’s palate, and don’t worry if it gets a little messy—that’s where the fun happens!