Blend together onion, tomatoes, serrano, ginger, garlic, cashews, turmeric, salt, cayenne, 1 teaspoon of garam masala, cumin, and coriander.
Pour the sauce into the inner liner of your Instant Pot. Rinse out the blender container using the water, and pour water into the pressure cooker liner as well.
Place the chicken on top and push it down into the sauce.
Set it at High Pressure for 10 minutes, and let it release pressure naturally.
Carefully take out the chicken and cut into bite size pieces.
Add coconut milk and the additional 1 teaspoon garam masala. Put the chicken back in to combine.
Garnish with cilantro if you'd like.
NOTES
Add pan-fried cashews or raisins as garnish before serving.
Variations.
I have anegg korma recipe that will show you how to make egg korma with the leftover chicken korma sauce.
Vegetable Korma: I'd actually cook the sauce and the veggies separately. Add 1/4 cup water to the sauce and cook as directed. Meanwhile, steam vegetables in the microwave or stovetop. Use a combination of cauliflower, green beans, and green peas to make an Instant Pot Vegetable Korma.
Vegetarian Options - Paneer, Mixed Veggies, or Cooked Chickpeas. In this case, add 1/4 cup of water to the sauce. To the cooked sauce, add your paneer, or chickpeas and heat through.
Beef Korma / Lamb Korma: Cut the beef or lamb into 2 inch chunks, and cook as directed for the chicken.
Substitute heavy cream or half and half for coconut milk if you prefer.
You could use chicken breasts instead, just butterfly them sideways so you have thinner pieces of chicken and cook for 6 mins
I ask you to add the coconut milk at the end since sometimes it can separate under pressure, leaving a greasy slick on top of the food.
For a slow cooker version, cook on low for 3-4 hours, or high 7-8 hours
That last spoon of garam masala is getting added at the end for fragrance.
You can hard cook some eggs and add them to any leftover korma sauce you may have.