Start by chopping all your vegetables into even-sized pieces for uniform cooking. Heat olive oil in a large pot over medium heat. Add onions, carrots, and celery, and sauté until softened and fragrant.
Add garlic and mushrooms, cooking until mushrooms release moisture. Stir in tomato paste, soy sauce, and herbs to deepen the flavor. Let everything cook briefly so the ingredients blend well.
Pour in vegetable broth and add potatoes along with the bay leaf. Bring the mixture to a boil, then reduce heat and let it simmer. Cook until potatoes are tender and the broth thickens slightly.
In a bowl, mix flour, baking powder, salt, parsley, plant milk, and olive oil. Stir gently until just combined; avoid overmixing. The dough should be soft but not sticky.
Drop spoonfuls of dumpling dough directly onto the simmering stew. Cover the pot with a lid and let them cook undisturbed. Steam will cook the dumplings until fluffy and tender.
Once dumplings are cooked through, remove the bay leaf and adjust seasoning. Let the stew rest for a few minutes before serving. This helps flavors settle beautifully.