Heat the olive oil in a large pot over medium heat. Add the ground beef and cook until browned, breaking it up with a spoon as it cooks.
Add the diced onion, minced garlic, and minced ginger to the pot. Stir and cook for 3 minutes until the onion softens.
Add the sliced mushrooms and cook for another 4 minutes until they start to release their liquid.
Pour in the diced tomatoes with their juice, soy sauce, and beef broth. Stir everything together and bring to a simmer.
Reduce the heat to low, cover the pot, and let the stew cook for 20 minutes, stirring once or twice.
Taste and add salt and pepper if needed. Ladle into bowls and top with the sliced green onions.