Creating Cozy One-Pot Chicken Stew with Fluffy Sourdough Dumplings is a delightful process. Follow these steps to ensure a successful outcome:

1. Heat the Oil: In a large pot or Dutch oven, heat the olive oil over medium heat.
2. Cook the Chicken: Add the chicken pieces to the pot, season with salt and pepper, and cook until browned, about 5-7 minutes. Remove the chicken and set aside.
3. Sauté the Vegetables: In the same pot, add the diced onion, garlic, carrots, and celery. Sauté until the onions are translucent, about 3-4 minutes.
4. Add Broth and Spices: Pour in the chicken broth, then add thyme, rosemary, and the browned chicken back into the pot. Stir well.
5. Incorporate Potatoes: Add the diced potatoes and bring the mixture to a gentle boil. Lower the heat and let it simmer for about 30 minutes, or until the potatoes and chicken are tender.
6. Prepare Dumpling Batter: In a separate bowl, mix the flour, baking powder, and salt. Next, add the sourdough starter and milk, stirring until a thick batter forms.
7. Add Dumplings: Drop spoonfuls of the dumpling batter over the simmering stew. Cover the pot and cook for an additional 15 minutes, or until the dumplings are fluffy and cooked through. Stir in frozen peas just before serving.