Wash, clean and slice the tomatoes. Peel, halve and slice the onions. Whisk eggs and milk. Season with salt, pepper and oregano. Cut bacon into pieces. Fry in a pan without fat until crispy.
Fry 1/4 of the onion slices in 1 tablespoon of oil until transparent. Add 1/4 of the tomato slices. Pour on 1/4 of the egg milk, cover and allow to set for about 10 minutes. Finally sprinkle some bacon pieces over it and heat it up. Do the same with the remaining vegetables, egg milk and bacon. Sprinkle fresh oregano over the omelettes as desired