Sauté the vegetables: In a large pot or Dutch oven, melt butter with olive oil over medium heat. Add onions, carrots, and celery. Cook for 5–6 minutes until softened. Add garlic and cook for another 30 seconds until fragrant.

Build the base: Stir in the flour to coat the vegetables (this helps thicken the soup). Gradually pour in chicken broth while stirring to avoid lumps. Add thyme, bay leaf, salt, and pepper.

Simmer the soup: Bring to a boil, then reduce to a gentle simmer for 15–20 minutes, until vegetables are tender and broth has slightly thickened. Stir in the cooked shredded chicken and cream. Keep warm on low heat while you prepare the dumplings.

Make the dumpling dough: In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Stir in the buttermilk and melted butter until a soft, sticky dough forms (do not overmix).

Add the dumplings: Drop spoonfuls of dough (about 1 tablespoon each) directly into the simmering soup. Cover with a tight-fitting lid and simmer gently for 15 minutes—do not lift the lid during this time, or the dumplings won’t cook properly.

Finish and serve: Once dumplings are fluffy and cooked through, remove the bay leaf. Adjust seasoning with salt and pepper as needed. Ladle into bowls and garnish with chopped parsley.