Cut the leek and the young onions into fine strips, the pumpkin flesh into cubes, the pork fillet into thin strips. For the marinade, mix the soy sauce with chili sauce, oyster sauce, cornstarch and sugar and pour over the meat. Season with salt and pepper. Heat the sesame oil in a wok pan. Drain the meat strips, add and stir-fry in the wok. Remove the meat. In the wok pan, now sauté the diced pumpkin with the leek and green onion strips. Add the meat and the remaining marinade and bring everything to the boil. Season with salt and pepper and serve in bowls.