Boil up plenty of salted water. Cut the steak into strips. Heat oil in a pan. Brown the steak strips in it and take them out.
Sprinkle flour into the hot frying fat and sweat it on. Add thyme. Deglaze with 350 ml water and wine, bring to the boil and stir in stock. Simmer the sauce for 6-8 minutes.
Meanwhile cook the noodles in boiling salted water for about 10 minutes. Stir the mascarpone first and then the green pepper (without stock) into the sauce.
Heat steak strips in it. Season to taste with salt and possibly some pepper stock. Drain the pasta very well and serve with the pepper cream sauce.