Mix both mustards together. Dab the meat dry, season with salt and pepper and coat with the mustard. Wrap the fillets with slices of bacon, overlapping slightly, and tie with kitchen twine. Wash thyme and shake dry
Heat the oil in a pan. Brown the meat in it for 2-3 minutes, then take it out. Deglaze the meat with white wine and start cooking. Place bay leaves and thyme on the bottom of an ovenproof dish. Place the fillets on top. Pour in white wine and cook in the preheated oven (electric cooker: 150 °C/ convection oven: 125 °C/ gas: see manufacturer) for approx. 25 minutes, sprinkle several times with roasting liquid
Peel and halve the onion and cut into thin rings. Heat the lard in a pot. Sauté the onion for about 5 minutes, then add the sauerkraut. Season with salt and pepper, cover and stew for about 20 minutes.
Wash and quarter the apples and remove the core. Cut quarters into slices and place around the fillets about 10 minutes before the end of the baking time. Remove meat from the oven and cover with aluminium foil for approx. 10 minutes and keep warm. Cut meat into slices and serve with sauerkraut and apples. Drizzle broth over it