In a large pot, melt the butter and saute the onion and carrots until the onions are tender. Add garlic and saute until fragrant.
Stir in the flour and cook for about 1 minute. Slowly pour in the stock, while stirring constantly.
Add the cream, chicken and seasonings. Bring to a simmer and allow to simmer gently while you make the dumplings, stirring occasionally.
To make the dumplings, whisk together the flour, baking powder, pepper, salt, and thyme.
Add the milk and melted butter to the dry ingredients, and stir until a sticky dough forms.
Stir the soup, then scoop small balls of dough (⅛ cup) directly into the soup.
Cover with a lid and simmer gently, without stirring, for 7-10 minutes, or until the dumplings are cooked through. To check if they are done, remove a dumpling and pull it gently apart with a fork. If it looks doughy on the inside, continue cooking for 2-3 more minutes.