Calvin Trillin published an essay entitled Missing Links in the New Yorker Magazine back in 2002 about boudin. It is a great read and you can find it right here: Missing Links
Anyway, here is a rundown of how it's made. First there is a lot of cutting and chopping of meats and vegetables. Pork butt, pork liver, lots of garlic, onion, celery, poblano peppers, jalapeno peppers, spices like cayenne pepper, chili pepper, salt, black pepper, white pepper and then to finish it off, cooked white rice, scallions and parsley.
At this point the mixture will be a little wet but the rice will absorb the liquid. Now it's time to stuff the casings. Hog casings are used for this. Then link the sausages if you choose and they are ready for the last and final step before eating. There are several ways to cook boudin, from boiling to steaming or even oven browning to brown off the casing so you can eat it. Usually boudin is squeezed out of the casing like squeezing a tube of toothpaste. You just suck the insides out of the skin and discard the skin. It may not sound appetizing but to quote Calvin Trillin, “I figure that about 80 percent of the boudin purchased in Louisiana is consumed before the purchaser has left the parking lot, and most of the rest is polished off in the car. In other words, Cajun boudin not only doesn’t get outside the state; it usually doesn’t even get home.”
All the more reason you'll just have to make your own! All you'll need is a Kitchen Aid Mixer with a meat grinding attachment and stuffer kit, a large stock pot and a rice cooker certainly helps. It's a labor of love like any sausage making, but you'll agree it is well worth the trouble when you are sucking the last morsels of boudin from the casings.