Add butter and onions to frying pan and caramalize until golden

Optional: In a separate bowl pour hot water over tomatoes. Wait for a minute or two until the skin of the tomatoes starts lifting. Chop tomatoes and add to the pan. Cook the tomatoes until everything looks well done and almost mushy.

Add egg omelette (or sunny side up) on top and cook until egg is well done. You can lightly mix the egg and tomatoes or cover with lid until it's well done.