Start by cutting your boneless, skinless chicken breasts into large cubes. This size helps the chicken cook evenly and remain juicy.
In your slow cooker, add the chicken cubes, diced tomatoes, diced onion, minced garlic, minced ginger, and minced jalapeño. These ingredients create a base of flavor that infuses into the chicken as it cooks.
Sprinkle the turmeric, ground coriander, ground cumin, paprika, chili powder, and garam masala over the chicken and veggies. Stir everything together to ensure the chicken is well-coated in the aromatic spices.
Pour in the chicken broth (or water) and coconut milk, then add the tomato paste. These ingredients will create a rich and creamy sauce that’s the hallmark of Chicken Tikka Masala. Stir until combined.
Cover your slow cooker and set it to low for 6-8 hours or high for 3-4 hours. The long cooking time allows the chicken to become tender and soak up all those wonderful flavors.
Once cooked, give everything a good stir. Taste and adjust seasoning if necessary. Serve hot, garnished with fresh cilantro, over rice or with naan.