Begin by cutting the chicken breast into bite-sized pieces and patting them dry.
Mince the garlic, grate the fresh ginger, and finely chop the half onion.
In a medium skillet, melt the butter over medium heat. Add the chopped onion and sauté until softened, about 2-3 minutes.
Stir in the minced garlic, grated ginger, and all the spices (garam masala, turmeric, cumin, and chili powder). Toast the spices lightly to release their aromas, about 1 minute.
Add the tomato paste and mix well, then add the chicken pieces. Cook the chicken until it's lightly browned on all sides, approximately 5-6 minutes.
Pour in the light coconut milk and stir to combine, bringing the mixture to a gentle simmer. Continue to cook until the chicken is cooked through and the sauce slightly thickens, about 5-7 minutes.
Season with a pinch of salt, taste, and adjust seasonings if needed.
Serve warm, pairing it with a side of steamed vegetables or a small portion of brown rice if desired.