Heat the olive oil in a large pot over medium heat. Add the chopped onion, carrot, and celery. Sauté for about 5 minutes until softened.
Stir in the minced garlic and chopped Baby Bella mushrooms. Cook for another 5 minutes until the mushrooms release their moisture and begin to brown.
Pour in the white wine and stir, Let it simmer for 2–3 minutes until the alcohol cooks off. Season with salt and black pepper.
Add pastina, the chicken broth, and water. Bring the soup to a gentle boil, then reduce the heat and let it simmer for 10 minutes.
Remove from heat and stir in the fresh parsley. Adjust seasoning if needed.
Ladle the soup into bowls and enjoy warm. Garnish with extra parsley or a drizzle of olive oil. Enjoy!