In a medium bowl, whisk together all marinade ingredients besides chicken. Toss chicken in marinade to coat well. Cover and refrigerate at least 1 hour, up to overnight.
In the Instant Pot in Sauté Mode, Normal Heat, heat the ghee. Add onion and cook until softened, about 4-5 minutes.
Reduce heat to Low Heat. Add serrano chiles, garlic, and ginger, and cook, stirring occasionally, until a nice, even toffee-brown color, about 10 minutes. Add 1-2 teaspoons water as needed if you notice the mixture sticking or drying out. If you cook this part over Normal Heat, monitor the mixture very closely. It will burn if you don't watch it well!
When mixture is a toffee brown color, add garam masala and paprika; stir well. Cook a few minutes, or until fragrant, adding a couple tablespoons of water to reduce sticking, if necessary.
Add the tomato sauce and stir well; transfer mixture to the blender and blend until smooth. Return sauce to pot and simmer for 15-25 minutes over Normal Heat or until thick like a paste, rather than like a sauce.
Add chicken, sliced bell pepper, fenugreek leaves, and salt. Secure lid and cook on Manual High Pressure for 6 minutes. Carefully Quick Release.
Add the coconut cream and stir until smooth. Taste and correct seasonings, adding more salt or fenugreek leaves as necessary. Serve over steamed cauliflower and top with plenty of chopped fresh cilantro.