Guys

In western Nepal they call it Pakku, In valley and easter nepal they call it Kabab. Yes it is different than Indian and Pakistani/Afghani kaboab 

The concept:
In olden days ppl dont used to eat meat everyday. Work was more physical. No transportation so you go everywhere by foot. Lots of calori used.
During Dashain they have lots of meat. And we know it i not good to eat lots of meat in short period of time.

Technology:
There were no refrigerators  to store meat for longer period of time. Fat get rancid if stored for longer period of time without preservative and coloin. There were no preservatives.

Fungus/Bacteria
They grow when there is a suitable media (food ) and when temperature is right. So when meat is kept at room temperature for long time it get destroyed (attacked by fungus/baceria). Our ancestors needed to preserve meat for longer period of time so that tey will be able to consume in controlled way

Technology used by Ancestors:

Making Pakku or Kabob so that they can store meat for longer period of time. 

How making of pakku /Kabab help preserves meat.?

We all know life needs water to survive. So if you take water out of meat fungus bacetrai cant grow on it ( remember sukuti? However sukuty is hard and difficult for kids and old people ).

While cooking all water will be driven out of the meat slowly, There will be lots of fat ( so no dissolved oxygen, like in case of water, even if fungus/bacteria come in contact with pakku they will die because of salt content in pakku as well as because of the fat. They will die because of lack of oxygen to breath and Osmosis (which will brust their cell wall)

Why pakku /kabab is tasty:
It is tasty because the way of cooking and all added spices. While cooking all the aroma from the spices will be extracted into fat and they will remain their. So while eating you will taste all the speices.But becarefull while cooking if you cook pakku in strong heat all aroma from different spices will be evaporated or will decomposed.

How to prepare Pakku

1. Lambs meat: Up to you how much. Remove most of the visible fat. (remember we dont need that much fat these days like our ancestors used to because a) lack of physical work b)  we do have refrigerators for preservation once cooked so take out all visible fat. 

2.Cut meat into pieces (size of your liking). Mix different spices like turmeric ( excess of turmeric may make food bitter)/coriender powder/ginger/cumin/garlic and garam masala spices Do not use readymade spices from Indian stores they are not good. Buy individual spices and grind/crush them yourself.
Pakku is not hot (piro) so do not use pepper. But you can use black pepper

3. Use olive oil, not those on bargain price and make sure that it is not a mixture of different oils.In olden days our ancestors used to use mustard oil. We have better option these days that is olive oil. Mix properly.
Leave for marination for one hr or so inside the freez or even at room tempe ( does not matter that much regarding the taste but refrigerator is betetr for safty purpose)

4. Cook in stainless steel utensils ( not coated with non stick coat, these are bad for health, once those non stick thing goes inside you it remains in your blood for ever, creating a lots of problem for you.)

5. In olden days they use to cook in a pot with thick base ( slow heating) but these days those pots are not available so heat control is very much iportant)

6.Heat the stainless steel pot (very hot) put marinated meat in the pot.cover. let it cook for five minutes then slow down the heat to almost half (almost 50% less heat than regular cooking) and cook for long time. check from time to time so that it is not over cooked. 

Usually you do not need to add water. do not use pressure cooker. It will destrpy all aroma from species.You can use pressure cooker without applying the pressure though.

When pakku is considered cooked?

Usually it is cooked more than rodinary cooking time to drive out all water.

What happens if you over cooked:

Meat will develop elastic character because of Gelatin. It helps to preserve meat longer but also destorys the "feel". (remember gummy candies) Overcooking also destroys the essential ingridents from the species. Therefore a little less cooking is betetr than the over cooking. Although main aim is to drive water out of the meat but it not good if all water is removed about 10-20% water must be there inorder to preserve water soluble vitamins and aromatic compounds.

I think Newars cook ta:khala almost similar way.Here they also put lots of skin,to extract as much gelatin as possible so meat is preserved  not mainly by removing water but by extraction of gelatin from skin during cooking.