Wash and clean the zucchini, quarter them lengthwise and cut into slices. Clean, wash and cut the peppers into strips. Clean the leek, cut into rings and wash thoroughly. Wash the meat, dab dry, season with salt and pepper.
Heat 2 tablespoons of oil in a frying pan. Fry the gnocchi for about 10 minutes, turning them over. After 4 minutes add vegetables and season with salt and pepper. Heat 1 tablespoon of oil in a second pan and fry the meat on each side for about 2 minutes.
Remove the meat and keep it warm. Pour cream into the pan, bring to the boil and loosen the frying set at reduced temperature. Wash marjoram, shake dry, pluck leaves from the stalks and add to the vegetable gnocchi.
Arrange meat and vegetable gnocchi with the cream sauce on plates.