Black pudding is actually made from congealed pig's blood. This makes it unusual in places like the Middle East, for example.
And here's the recipe:
Yield: 6 servings
Put the bread cubes to soak in the milk in a warm oven. Do not heat the milk beyond blood temperature! Have the blood ready in a large bowl, and pour the warm milk and bread into it. Stir in the cooked barley. Grate the beef suet into the mixture and stir it up with the oatmeal.
Season with the salt, pepper and mint.
Have ready 2 or three large roasting pans. Divide the mixture between them ~- they should not be more than 3/4 full. Bake in a moderate oven -- 350 Fahrenheit ~- for about an hour or until the pudding is well cooked through. This makes a beautifully light pudding which will keep well in a cold larder.
Cut into squares and fry till heated through and the outside is crisp, in bacon fat or butter. Delicious for breakfast, or for supper with fried apples and mashed potato.