Heat the olive oil in a large deep stock pan over high heat. Add mushrooms and cook 10 minutes, stirring every 2-3 minutes.
Reduce heat to medium and add the chopped onion. Cook an additional 3 minutes.
Add bone broth – if you want a lighter and brothier soup, use 2 packages, if you want a denser soup, use one package of broth.
Bring broth to the simmer with the mushrooms and onion base, add the green beans and corn and simmer 5 minutes until tender.
Add the cubed tomatoes and cook 2 more minutes. Taste for salt, add more salt.
For complexity and flavor, you can finish this soup with more olive oil or a squeeze of lemon juice.