Gather pork shoulder, pork liver, cooked rice, onion, celery, garlic, green onions, parsley, cayenne, black pepper, white pepper, thyme, salt, and sausage casings
Cut the pork into chunks and place in a pot with water, salt, and seasonings
Simmer until the pork is tender and fully cooked
Remove the pork and reserve some cooking liquid
Cook the liver separately until fully cooked, then chop or grind it
Sauté onion, celery, garlic, and green onions until soft
Grind or finely chop the cooked pork and liver
Mix the meat with cooked rice, sautéed vegetables, parsley, and seasonings
Add reserved cooking liquid gradually until the mixture is moist but not soupy
Taste and adjust salt and spices
Stuff the mixture into sausage casings
Twist or tie into links
Chill the boudin before cooking or serving
Steam, poach, grill, or pan-fry as desired