Peel and chop the onions. Mix with beer, mustard and 1 tablespoon of oil. Wash the meat, dab dry, brush with marinade and marinate covered for about 1 hour. Turn several times.
Meanwhile cook the pasta in boiling salted water for about 10 minutes. Clean and wash the radishes and peppers. Quarter the radishes and cut the bell peppers into pieces. Wash the rocket, dab dry and cut into small pieces.
Drain the pasta and chill in cold water. Mix sour cream, 1 tablespoon of oil and lemon juice. Season with salt, pepper and sugar. Mix noodles, radishes, paprika and rocket with the sauce and marinate for about 15 minutes.
In the meantime, remove the meat from the marinade and let it drip off a little. Heat 1 tablespoon of oil in a frying pan, fry the steaks for 10-12 minutes while turning, season. Remove and serve with the pasta salad.