Peel onions and garlic. Quarter onions and cut into slices, chop garlic finely. Clean, wash and chop the bell peppers and celery, leaving some celery green aside. Quarter pumpkin, remove seeds, wash and chop.
Dab meat dry. Heat oil in a roasting pan. Brown the meat in it in portions and take it out. Fry the prepared vegetables and oregano briefly in the frying fat. Add meat again. Deglaze everything with cola and about 1 l water. Season with salt, pepper, chili flakes and Tabasco.
Cover and cook in a preheated oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer) for approx. 2 hours. Season goulash with salt and pepper. Finely chop the celery green and sprinkle over the goulash. Serve with baguette.