Haggis is marvellous stuff. Who would have thought of mincing sheep offal, mixing it with oats and stuffing it into a sheep's stomach? It's kind of bizarre, but also totally delicious. For most people, haggis means Burn's Night, which happens on the 25th January. But there's no reason why you shouldn't eat it all year round, and you can also use it in scotch eggs, lasagne, sausages etc.
The consumption of lungs is banned in the US, but you could substitute some lamb meat for that. If you can't obtain a stomach, you can use sausage casing instead - it's only there to hold the filling together while it cooks.
To make the haggis filling
Wash the pluck in several changes of cold water. The heart, liver and lungs are connected by a gristly thing which I think is the windpipe - cut the organs off this, and discard it. Place the organs into a pan with enough water to cover them. Bring to the boil, and simmer for 2 hours, adding more water if necessary.
If you are using a stomach, turn it inside out and rinse with boiling water. Leave to soak in water overnight. If you are using sausage casings, soak them in cold water for at least an hour.
Peel and finely chop the onion. When the offal is cooked, remove it from the pan (but keep the cooking water), chop it into large chunks and pass it through a mincer using the coarse plate. Alternatively you could whizz it in a food processor, but be careful you maintain a crumbly texture rather than a mush.
Mix together the oats, onions, minced offal and seasoning. Add just enough of the cooking water the create a stiff, dry paste. If you are using a stomach, spoon in the mixture until the stomach is half full (the filling expands a lot during cooking). Sew the top shut, and prick some holes in the skin to let air escape. For sausage casings, cut several pieces about 30cm (1 foot) long and tie a knot in one end. Using a funnel, spoon some of the mixture into the casing. Again, only half fill the casings. Tie a knot in the open end, and prick some holes in the skin.
Boil the haggis or sausages in plenty of water for 2-3 hours.
Split the haggis open and spoon some of the filling on to a plate. Serve with bashed neeps (mashed swede or turnip - the orange one), and tatties (mashed potato). And a shot of whisky. If it's Burn's Night, you'll also need a band of pipers and drummers playing 'Scotland the Brave' and somebody to recite 'Address to a Haggis' by Robert Burns.