1 sheep’s pluck (liver, heart, lungs - if no lungs then add same weight as liver in minced lamb/mutton. You can use all mince if you don’t have the offal). It will lose about 25% of its weight when you cook it, but you need to weigh it went cooked to accurately calculate the rest of the ingredients.
The rest of the ingredients are given for 1kg of pluck (when cooked) so scale accordingly:
350g of pinhead oats (eg if pluck weighs 500g then 250g)
240g suet (or replace with 85% lard 15% flour)
2 medium onions
2 tsp salt
1 tsp ground pepper
2 tsp cayenne pepper
1 tsp mixed herbs
1 tsp ground nutmeg
1 tsp paprika
1 tbsp cider vinegar (or lemon juice or other vinegar)
Approx 600ml liquid (ideally the water from cooking the pluck - see below)
Simmer the pluck in about 2 liters of liquid for 2 hours. Top up if looking dry. You want to get to something less than a liter (depending on pluck size) when it is cooked to avoid wasting too much of the flavour. Or you can pressure cook for an hour with less liquid.
Finely chop the onions and fry gently until soft.
Mince or finely chop the pluck. Easier if you wait for it to cool. It needs to be small bits, but doesn't matter too much as it all kind of turns to mush with the liquid later.
Mix the minced pluck with everthing else in a large bowl.
Taste and adjust seasoning if necessary.
The mixture should be definately wettish, but not liquid. The grains will absorb water as it cooks.
Traditionally haggis is cooked in a sheeps stomach. However we didn't get this back from the abattoir, plus it is difficult to just how much to fill them to avoid bursting.
If using trays or a bowl then cover with tin foil and steam in a pan or in a cook in a bain marie in the oven for about 3 hours or pressure cook for 1 hour. If using the stomach you simmer for about two hours. I would think you might want a slightly wetter mixture if using a steaming method as I would imagine some liquid would get through the stomach.