For the noodles, cook the noodles in boiling salted water according to the package instructions. Peel onion and cut into fine cubes. Heat 1 tablespoon butter. Sauté the onion cubes in it until translucent. Add the frozen peas and stew covered for about 5 minutes.
For the fish chop the bread finely in the universal chopper. Grate cheese, mix both. Whisk eggs with salt and pepper. Wash the fish, dab dry and cut into 8 pieces. Turn the fish one after the other in flour, egg and breadcrumb mixture. Heat oil, fry fish in it in 2 portions on each side for about 3 minutes.
Wash and finely chop the parsley. Drain the pasta, mix with parsley and peas.
For the lemon butter, wash the lemon hot, grate it dry and peel it into strips with a zest ripper. Squeeze the lemon. Melt 4 tbsp. butter, stir in lemon juice and zest. Season with salt and pepper. Arrange noodles and fish. Sprinkle fish with lemon butter.