Wash the pork fillet and remove the silver skin. Mix the marinade ingredients together well.
Place the pork fillet with the marinade in a freezer bag, seal it, shake to coat thoroughly, and refrigerate for at least 2 hours or preferably overnight.
Preheat the oven to 200°C (392°F) with top and bottom heat. Place the meat with the marinade in a baking dish and cook on the middle rack for 30 minutes, basting with the marinade every 8-10 minutes. The meat is done when the internal temperature reaches 63°C (145°F).
Remove the fillet from the oven and let it rest for 5 minutes. Slice into 1.5-2 cm thick slices and keep warm.
Pour the cooking liquid from the baking dish into a saucepan and heat over medium heat. Whisk in 200g cream cheese, stirring constantly, until the sauce comes to a boil. Taste and adjust the seasoning with salt and spices as needed.
Serve the pork slices with the sauce, accompanied by spaetzle.