Mix and boil.
Cut tomatoes, onions, and potatoes into bite-sized pieces.
Pour olive oil into a pan.
Sauté the onions first to bring out their aroma.
Add potatoes and tomatoes and stir-fry together.
Add water and salt, and bring to a boil.
Simmer gently over low heat for 20 minutes.
Serve the finished stew in a bowl.