Heat the olive oil in a large pot or Dutch oven over medium heat.
Add the chopped onion and sauté for about 5 minutes, or until translucent.
Stir in the minced garlic, cooking for an additional minute until fragrant.
Add the sliced mushrooms, carrots, and celery. Sauté for about 10 minutes, allowing the mushrooms to brown and the vegetables to soften.
Sprinkle in the dried thyme and rosemary, stirring to combine with the vegetables.
Add the drained white beans, vegetable broth, and diced tomatoes, including the juice. Bring the mixture to a gentle boil.
Reduce heat and let simmer for 15-20 minutes, stirring occasionally, until the stew thickens slightly.
Season with salt and pepper to taste.
Serve hot, garnished with fresh parsley.