For the Boudin Noir Spices:
Toast and grind the black pepper, cayenne pepper, and cinnamon, then combine them with the salt and set them aside.
For the Boudin Noir Base:
Clean the pork casings in cold water, taking care to rinse out the inside too. Clean the meat of any sinew. Sweat the pork fat and onions in a covered pot. Blend the blood to ensure a smooth texture. Grind the guanciale and lean pork using a small die. When the onion and fat are translucent put into a large mixing bowl and add 3 tablespoons of the Boudin Noir Spices. Start to carefully poor the blood into the onion mixture. When ½ of the blood is incorporated start to add the pork, guanciale, eggs, and cream.
To Assemble and Serve:
Using a funnel attachment, prepare the casing and start to ladle in the blood mixture. When all is encased, close the sausages and poach them in water until they start to firm up. Remove the sausages from the water and let them rest until they firm up more. This can be served as links, or taken out of the casing and served as a pudding or spread.