Heat the oil and fry the fillet vigorously in it. Season with salt and pepper, then remove. Fry the mushrooms and onions in the hot frying fat. Pour in the broth and stir in the green pepper. Place the fillets on top of the mushrooms and cover and let simmer for approx. 15-20 minutes.
Chop the chervil to garnish.
Remove the meat from the sauce and keep warm. Put the chervil in the mushroom sauce. Pour in the cream and sprinkle in the sauce thickener while stirring. Bring to the boil again and season to taste.
Cut the pork fillet into beautiful slices and serve with the asparagus and mushroom sauce.