Preheat oven to 180°C. Melt butter in a pan over medium heat and sauté meats until brown. Remove meats, add onion and cook until translucent, about 5 minutes. Add remaining ingredients and bring up to a simmer. Transfer sauerkraut to a baking dish and arrange meats on top.
Choucroute can be chilled until ready to serve at this point, and then baked for 40-45 minutes, until bubbling. To hold while entertaining, reduce oven temperature to 95°C and cover loosely with foil.
Serve choucroute with a variety of mustards, sour cream (that’s Anna’s choice) and a side of buttered, boiled potatoes.