Traditionally, one uses a roast for this dish. I have had good luck using round steak. Well, really traditionally, one uses horse meat… Wash and dry beef, place in large cook pot or bowl; chop onion and place all other ingredients (except for sour cream and corn flour) in bowl to marinate.
Place in refrigerator to marinate, turning every day to allow all of the meat to become infused with spices. Continue marinating 4-7 days. Remove meat from marinade. Bake in pre-heated oven at 350°F with small amount of water to prevent burning and sticking.
Cooking time varies. When internal temperature is approximately 145°F roast is medium rare. At 160°f roast is medium. Cook for roughly 12-15 minutes per pound.
Mix corn flour and water to make paste for gravy. Pour meat juices from pan and marinade into saucepan, bring to boil and add corn flour to thicken. Add Maggi seasoning to taste.
Add sour cream to gravy creamy and serve with dumplings (or Spaetzle) and a vegetable. Good choices for a vegetable include creamed corn, cauliflower, or new potatoes.