Still adjusting this recipe, but after much experimenting, this immensely flavorful favorite can be made at home!
This -IS- a complicated recipe so be patient, and you WILL need some exotic ingredients so plan a trip to an Indian market. Fresh is always best.

Chicken Curry

Ingredients:
(Base/Gravy)
1 Lg. Red Onion, sliced or loose chop
3 Tomatoes (pref. Roma tomatoes, peeled, gutted, loose chopped)
2 Tbsp. Cashews (whole or pieces, pref. raw and unsalted)
2 Bay leafs (whole)
3 Cardamom pods (whole or 1/4 tsp. ground)
3 Cloves (whole, or 1/4 tsp. ground)
1" Cinnamon stick (or 1 1/2 tsp. ground)
2 tsp. Garlic, sliced or minced
1 tsp. Ginger, sliced, minced or paste
1 tsp. Butter (or substitute)
1 tsp. Black pepper (fine grind)
1 1/2 cups water (or use chicken broth to enhance flavor)
(Curry)
2-3 Tbsp. Butter or Oil
2 tsp. Cumin Seeds (whole)
1 or 2 Chili Peppers (fine-diced, adjust to taste, I use 1 serrano and one jalapeño)
1" Ginger Root, sliced thin (Aprx. ~1 Tbsp.)
1/2 tsp Turmeric (ground)
3 Tbsp. (yellow) Curry powder
1 tsp. Chili powder (adjust to taste)
1/2 tsp Corriander (seed) powder
1/2 tsp. Garam Masala
1 Tbsp. Salt (adjust to taste)
1 tsp. Kasoori Methi (a.k.a. Fenugreek Leafs, fine chopped if fresh, ground fine if dried)
2 Tbsp. Cilantro (fine chopped) +more for garnish (garnish optional)
1 cup Chicken (pre-cooked and cubed ~1cm)
Yogurt for garnish (optional)

Directions:
(Base/Gravy)
In large covered pan, combine Onion, Tomatoes, Cashews, Bay Leaf, Cardamom, Cloves, Cinnamon, Garlic, 1 tsp. Ginger, 1 tsp. butter, Black pepper and Water (or Chicken Broth) and bring to a boil. Boil covered for ten minutes.
Allow to cool. Blend until smooth and set aside.
(Curry)
In large covered pan, sauté cumin seed, diced chili and slivered ginger in 2-3 Tbsp. butter or oil until fragrant. Add turmeric, curry powder, chili powder, coriander seed, garam masala, salt, kasoori methi and base/gravy.
Stir together and boil covered for 5 minutes.
Add chicken and 2 Tbsp. cilantro. Stir and boil covered for another 5 min.

Garnish with yogurt and a pinch of chopped cilantro. Serve with seasoned rice and/or naan.