Step 1: Prep the Base ; Chop onion, mince garlic, and grate ginger. Blend cashews with water to make a paste if using.
Step 2: Add Ingredients to Slow Cooker : Add chicken pieces to the bottom. Add onions, garlic, ginger, spices, and salt. Pour in yogurt, coconut milk, tomato puree, and oil. Stir gently to combine.
Step 3: Slow Cook : Cover with the lid. Cook on high for 4–5 hours or on low for 6–7 hours. Stir once halfway if possible.
Step 4: Final Adjustments : If sauce is too thin, simmer uncovered for 10–15 minutes or stir in a cornstarch slurry. If too thick, add a splash of coconut milk or broth.
Step 5: Serve : Fluff cooked basmati rice. Serve korma over rice. Garnish with cilantro.