Heat 2 tablespoons of the ghee in an Instant Pot using the Sauté setting. Add the chicken, shallots, and onion and sauté for 8 minutes, until the chicken is browned and the onion is translucent. Add the remaining 4 tablespoons ghee, the tomato puree, tomato paste, lemon juice, garlic, cardamom, cinnamon stick, bay leaves, ginger, garam masala, cumin, salt, turmeric, and fenugreek and stir to combine. Secure the lid and select the meat/stew setting, or select the Pressure Cook and Manual setting and cook at high pressure for 10 minutes.