Brown the beef, in batches, in a bit of olive oil / lard. Removing from the pan and setting aside.
Add another couple tablespoons of oil / lard to the pan and saute the onions and mushrooms until the mushrooms have browned.
Add the minced garlic and saute for a minute.
Add the flour and saute again, for another minute.
Add half of the beef stock to deglaze the pan, then add the remainder of the stock and the heavy cream.
When the mixture has thickened slightly, add the beef back into the pot. Simmer for a couple minutes.
Add some of the liquid to the sour cream, mixing together, then adding it to the pan. Stir to combine.
Combine the seasoning paste ingredients in a small bowl. Add the mixture to the pan and let simmer for a couple minutes, tasting for any needed salt and pepper.
Serve over potatoes or egg noodles.