In a large stockpot, heat oil over medium-high heat, add rice and stir to coat. Let the rice cook for a couple of minutes to lightly toast the grains. Stir in dried herbs and season with salt and pepper. Add broth and 1 cup of boiling water and stir well. Bring the mixture to a low boil, cover, reduce heat to medium-low, and simmer for 45 to 60 minutes or until the rice is tender.

In a frying pan, heat oil over medium-high heat. Once hot, add the onion, garlic, carrots, and celery, and cook for 8 minutes or until softened. Add mushrooms, and stir to combine. Cook for 6 to 8 minutes, occasionally stirring, until the mushrooms are soft and slightly golden.

When the rice is still al dente, add the contents of the frying pan and stir to combine.

Remove from heat, adjust seasoning, garnish with spring onions and serve.