Trim the green beans and cut the tomatoes in half. If you use bigger tomatoes, cut them into smaller pieces.
Place the green beans and 1/4 cup water in a large saucepan. Bring to a boil. As soon as the water comes to a boil, cover the pan, turn the heat down, and cook for about 5 minutes.
Add the butter or oil, garlic powder, tomatoes, salt, and pepper.
Turn the heat up if needed and cook for another 2 minutes until the tomatoes are soft.