Peel, wash and cut the sweet potatoes into pieces. Cover and cook in little boiling salted water for about 20 minutes. Peel carrots, cut them in half lengthwise and cut them into thin slices. Clean, wash and halve the beans and cook in boiling salted water for about 8 minutes.
Add the carrots 3 minutes before the end of the cooking time. Drain the vegetables and rinse with cold water.
Wash the meat, dab dry and cut into strips. Season meat with salt. Heat oil in a large pan. Fry the meat for about 3 minutes, turning it over. Drain the potatoes, add butter and mash into puree
Season to taste with salt and pepper. Drain the corn.
Add carrots, beans and corn to the meat. Wash parsley, shake dry, pluck leaves from the stalks and chop finely, except for a few for garnishing. Add parsley to the vegetables. Season to taste with salt and pepper.
Arrange the puree in the middle of the pan. Garnish with parsley.