Mix all ingredients for the marinade in a large bowl and toss the chicken thighs in it to coat. Marinate for 1 hour to overnight.
For the sauce, heat the butter and sauté the onion and ginger/ garlic paste in it until fragrant and beginning to brown.
Add the cream, bring to a simmer and set aside.
Brown the chicken pieces in a large pan or grill. Pour the sauce over the chicken and simmer for 10-12 minutes or until the chicken is cooked.
Adjust the final flavor with salt and lemon juice. Adding a little more chili if desired. Makes about three pounds.