I don't know how to cook the white pudding but with the black one you slice it and fry it in a pan and have it as part of a traditional english breakfast with eggs (fried, scrambled, poached..) bacon, mushrooms, tomato, beans......it's up to you. I would dry fry it if i were you as it contains quite enough fat already!! If you want to you can also split it and then grill it, or reheat it in warm water. I have 3 recipes that you could have from the Gary Rhodes book 'New British Classics' but his recipes are always quite long so i will tell you what they are and if you want them let me know and i will send them. They are -
1. Scallops with Grilled Black pudding a l'orange (sorry can't add accents when typing here)
2. Braised Beef Olives with Black Pudding, butter, onions and mushrooms
3. Rack on Black (lamb and black pudding tied together in a sausage shape)

K