I'd initially written out a much longer, slightly hard-to-follow recipe up. Here's the recipe, simplified. This is pretty much my mum's recipe, just written out by me as I'd do it, following a quick consultation with my mum.

As I've said earlier, the spices used in this dish are meant to be reminiscent of the spices typically used on chicken roasted a tandoor, therefore I'll be calling for a pre-mixed "tandoori masala". If you can't find a good one, or aren't sure about the proportions, sub with another flavouring spice/rub of your choice. Just remember to change the name of the dish.

Pro-tip: Feel free to substitute the chicken with paneer, firm tofu, mushrooms (left whole), potatoes, cauliflower, or broccoli. If going for meat, this recipe would work with pork, but not so much with red meat, although adjustments will need to be made. The lighter the star element, the lighter the spices need to be. I highly recommend the paneer option.

I'm going to write the recipe out for this dish done in three ways. I'll add ingredients as required for each as we go.

TO ROAST:

What you'll need

• Chicken (thighs and drumsticks are the best for this; skinless -- you could easily adapt this into a saucy platter of wings, too, keep the skin on, in this case)
• Red Onions/Shallots, White Onions (optional)
• Garlic, Ginger (crushed down into a paste; ratio 2:1; keep some garlic aside for other use)
• Fresh Green Chillies
• Coriander (leaves and stems)
• Greek Yoghurt
• Green Capsicum (Bell Pepper)
• Pre-made spices: Tandoori powder (my recommendation is Rajah's Tandoori masala/powder. It's objectively the best). We'll be using a lot of this
• Powdered Spices: chilli powder, Kashmiri chilli powder, black pepper, white pepper, turmeric, garlic powder, coriander powder
• Salt, Black Salt (also known as Himalayan Pink Salt), MSG (all mentions of MSG are my own additions that my mum's since added to the recipe)
• Butter/Ghee
• A Neutral Oil (Sunflower and Rapeseed are recommended)
• A lemon (optional)
• Optional smoke element (I'll leave this up to you)

Pre-cook

• Portion out your chicken. Make deep gashes in the meat and poke over with a fork. Throw into a large bowl
• Pour out some Greek Yoghurt onto a fine strainer/cheesecloth. Allow it to drain free of liquid
• Add your powdered spices (hold the MSG). Go heavy on the Kashmiri chilli powder, then mix thoroughly. Top with an even heavier amount of the Tandoori powder. Mix together until the chicken takes on a good colour
• Finely-chop some red onions/shallots, and add to the bowl along with with some crushed garlic, chopped ginger, minced chillis, and some chopped coriander stems. Mix again and leave in the fridge for an hour or two before taking it back out
• Add a few spoons of the strained yoghurt to the bowl and mix until the chicken is lightly coated, top up with some more Tandoori powder, Kashmiri chilli powder, and Black Salt
• Add some oil, mix everything together, and return to the fridge for another six to eight hours
  
• Take the bowl out thirty minutes prior to cooking, give it a thorough mix, dust with Tandoori powder, MSG, and salt to preference

The cook

• Roast this in an oven with some thick-sliced onions and capsica (or other veg of your choice). Alternatively, grill. Attempt to acheive a slight char
• Halfway through, dust with a little Butter/Ghee, and dust with just-cracked black pepper
• Rest, and serve hot with a drizzle of lemon juice. Garnish with minced onions and a dressing of coriander leaves

Serving

• Mashed potatoes, or Bengali-style fried potatoes are a great side dish option, as is a Kachumber salad (think Pico, but with no lime juice and a load of added chopped cucumber), but I'll recommend a cold cabbage salad with a nice vinaigrette, instead
• In case you're curious: Bengali-style fried potatoes are sliced potatoes, rubbed with salt and turmeric, fried in Mustard oil -- the good stuff is nigh-impossible to find outside of India; the best brand is Engine oil ^{I know...} -- or a neutral oil until softened, but slightly-crisped around the edges, then topped with a spice rub

TO CURRY

Additional ingredients

• Peeled Plum Tomatoes, Concentrated Tomato paste
• Whole spices: Bay leaf, clove (just need one or two), black peppercorns (again, just a few), cinnamon stick (small, and optional), dried chillies
• Potatoes (you're about to love these)
• Malt/Red Wine Vinegar
• Chicken Stock/Water
• Soy sauce/Worcester sauce (optional -- these are things I've added over time)

Pre-cook remains the same
Pro-tip: Feel free to make this with your pre-roasted, grilled chicken. Simply add your chicken in later into the cook.

The cook

• Cut your potatoes in half, rinse, and rub with salt
• Toast your cloves and peppercorns off in a dry pan, transfer out and grind them down to a coarse powder
• Add some oil to the pan and fry your potatoes (cut side down) off on a medium-high heat with some added salt until golden-brown. Transfer out
• Fry off some very finely-sliced/minced onions on a medium heat with a pinch of salt, stir for a few minutes until the onions soften, add your garlic and ginger, stir, add your cinnamon stick, if using
• Add a pinch of turmeric, stir, and chase with the rest of your powdered spices
• Throw in some chopped chillies, chopped coriander stems, and a little more minced garlic
• Add a little Tandoori powder
• Make some space on the side, and cook out some tomato paste, mix together and cook for a minute or two
• Increase the heat to high
• If required, add a little more oil, and throw your marinated chicken (with the marinade) in. Chase with a pinch of salt and a dose of Tandoori powder. Allow to cook on medium-high for a few minutes, stirring occasionally
• Throw your potatoes back in along with some thick-chopped capsica, salt, a little Tandoori powder, MSG to taste, and stir through
• Throw in your tinned tomatoes (crush them as they go in) along with their juice, top with some black pepper and dried chillies to taste
• Cut the heat back to medium
• Allow to cook for 10-15 minutes, stirring occasionally (the smaller your chicken, the less time this step will take)
• Add a little more Tandoori powder, the bay leaf, some sliced chillies to taste, and your peppercorn clove powder
• Deglaze the pan with some vinegar/soy/Worcester sauce, and stir together
• Add your stock/water, stir through, and bring to a boil for a minute, before cutting the heat and allowing to simmer on a low heat until the chicken and potatoes are cooked-through. Remove the bay leaf
• Taste for seasoning, adjust as required
• Top with some ripped coriander and cut the heat
• Allow to rest for twenty minutes before serving. Gently reheat on the stove if required

Serving

• There are no questions. There is an order to this (or at least, my mum enforces an order, and no one argues with my mum)
• White rice (honestly, do the rice how you like. Everyone's different) topped with a little melted ghee. Serve some sliced raw onions on the side with some chilli and salt (this is almost tradition in Calcutta)
• Serve a small, green dish first. Either some fried spinach with potatoes (or a quick palak paneer), my mum's peppered potatoes and green beans dish (highly recommended), or something a little bitter. Make sure the taste is as far from the chicken as possible
• Finish the meal with your tandoori chicken curry
• Maybe have some aachar (Indian pickle) on the side. Go for either spicy garlic, lime, or mango. They're great with this

TO SANDWICH

This is by far the easiest version. My school-mates would regularly rob me for these

Additonal Ingredients

• Tomato sauce (NOT ketchup, that's too sweet, but if there's no alternative, you may use it)
• Hot sauce (whatever you like, honestly)
• Bread
• Aamchur (dried mango) powder (optional)

The cook

• Chop up your chicken into very small pieces
• Add all your powdered spices, tandoori powder, MSG, salt, and a lick of yoghurt
• Chop some onions finely. Same applies to garlic, ginger, and coriander stems
• Fry everything off in ghee/a neutral oil
• Just before finishing, stir in your sauces (don't use too much), cook through, deglaze with some vinegar, and set aside, top with a small amount of minced raw onion
• Toast off some slices of plain white bread (or whatever bread you like) in the same pan on both sides with a little butter/oil
• Assemble your sandwiches, press down in the pan
• Optionally, dust with some Aamchur and Black Salt
• Serve

And that's it!

I have so many stories around this dish, and it really is a treat of a meal. Hope you enjoy!

Sudden co-incidence: My mum just called as I was finishing this up (literally writing the word "enjoy"). She's currently taking off to Vietnam for a few days. Her first vacation in years. She really deserves it.

Apologies for any typos, etc. I'll give this a once over in the following days.