Turn on Saute mode to pre-heat your Instant Pot. Add butter (or ghee), onions and sauté for a minute.
Add minced ginger and garlic, and cook for 2-3 minutes, until onions become translucent.
Add tomato, cashews, salt and spices. Stir well and saute for 2-3 minutes, until tomatoes begin to soften. cancel Saute.
Add water and use that to deglaze the brown bits that may have stuck to the bottom.
Lock lid in place and select Pressure cook/Manual for 3 minutes at high pressure, on sealing mode.
Using an immersion blender, puree the cooked ingredients into a smooth sauce.
Turn on sauté and add paneer cubes, butter, dried fenugreek, heavy cream and simmer. Garnish with fresh cilantro and serve with Naan or Jeera rice.