Preheat a frying pan, pour in vegetable oil. Finely chop the onion, fry for a few minutes. Then grind the bell pepper, add to the onion, fry for 3-4 minutes.
Then cut the tomato, add to the vegetables and fry for another 3-4 minutes. Chop green onions and parsley and add to the pan with vegetables, cook for 3 minutes.
Crumble the feta cheese, add to the pan and cook everything together for 2-3 minutes.
At this time, beat the eggs, pour into the pan, gently mix the contents, salt, and pepper, cover, and cook the omelet with cheese (feta cheese) and vegetables over low heat until desired. (I like a completely cooked omelet.)
Serve mish-mash – a Bulgarian omelet with tomatoes, peppers, and feta cheese – right in the skillet.