Recipe for haggis from this BBC page:

Preparation time overnight. Cooking time over 2 hours. Serves 4-6

Ingredients
1 sheep's stomach or ox caecum, cleaned and thoroughly, scalded, turned inside out and soaked overnight in cold salted water
heart and lungs of one lamb
450g/1lb beef or lamb trimmings, fat and lean
2 onions, finely chopped
225g/8oz oatmeal
1 tbsp salt
1 tsp ground black pepper
1 tsp ground dried coriander
1 tsp mace
1 tsp nutmeg
water, enough to cook the haggis
stock from lungs and trimmings

Method
1. Wash the lungs, heart and liver (if using). Place in large pan of cold water with the meat trimmings and bring to the boil. Cook for about 2 hours.
2. When cooked, strain off the stock and set the stock aside.
3. Mince the lungs, heart and trimmings.
4. Put the minced mixture in a bowl and add the finely chopped onions, oatmeal and seasoning. Mix well and add enough stock to moisten the mixture. It should have a soft crumbly consistency.
5. Spoon the mixture into the sheep's stomach, so it's just over half full. Sew up the stomach with strong thread and prick a couple of times so it doesn't explode while cooking.
6. Put the haggis in a pan of boiling water (enough to cover it) and cook for 3 hours without a lid. Keep adding more water to keep it covered.
7. To serve, cut open the haggis and spoon out the filling. Serve with neeps (mashed swede or turnip) and tatties (mashed potatoes).