Fry chopped onions and mushrooms in a pan with high sides for about 10 minutes.
Add chopped meat.
Fry all together for another 10 minutes. Add mustard, tomato paste, capers and thyme leaves. Stir, pour half a glass of water and simmer until the meat is soft for about 30 minutes.
Add sour cream, cream, bring to a boil, season to taste and simmer for another 5 minutes.
Serve Stroganoff- style pork with mushrooms with any side dish.