Grind cashews into a smooth paste with 2 tbsp water.
Whisk cashew paste, heavy cream, yogurt, ginger paste, garlic paste, garam masala, and salt in a bowl.
Coat cubed chicken breast in marinade and rest for 45 minutes.
Thread chicken onto skewers.
Grill on a hot skillet with butter for 10 minutes, flipping until cooked and slightly charred.