In a small bowl, combine the mix powder, paprika, Kashmiri chili powder, madras curry powder, kasoor methi and salt. This is your spice mix.
Heat 4 tbsp vegetable oil in a pot over medium heat until it shimmers.
Toss in the cinnamon bark and let cook a few seconds. You will see little bubbles forming around the bark.
Add the garlic ginger paste and cook until it stops spluttering.
Turn the heat to medium low. Add the spice mix and stir continuously until it starts to smell really good - around 30-40 seconds. Watch it carefully. If you burn the spices at this point you have to start over.
Add the diluted tomato paste and stir to combine. Turn the heat up to medium. Cook for 1 minute.
Add the onion paste and turn the heat up to medium high. Cook, stirring occasionally for about 4 minutes. The curry will darken a bit as it cooks. Don't worry if it seems a bit dry. The chicken will release juices as it cooks and you should be left with a nice amount of sauce.
Turn the heat down to medium low. Add the chicken and stir. Cover and simmer until the chicken is done. It's done when you measure the internal temperature and it says 170F, about 12-15 minutes. An instant read thermometer is a handy thing to have here...
If the curry is a bit thick add a bit of water or chicken stock and stir. Add a squeeze of lemon juice. Let the chicken madras simmer another minute or so. Taste for salt and adjust as needed.
Garnish with a bit of cilantro and diced red finger hot chili pepper if desired.