Heat the olive oil in a large pot over medium heat. Add the ground turkey and cook until it is no longer pink, breaking it up as it browns.
Stir in the onion and garlic. Cook for 3 minutes until the onion softens.
Add the sweet potatoes and carrots. Pour in the chicken broth, then stir in the thyme, salt, and black pepper.
Bring the mixture to a boil, then reduce the heat and simmer uncovered for 15 minutes until the sweet potatoes are tender.
While the stew simmers, make the dumplings. In a bowl, combine the flour, cheddar cheese, and baking powder. Stir in the milk and melted butter until a soft dough forms.
Drop spoonfuls of the dough onto the surface of the simmering stew. Cover the pot and cook for 12 minutes without lifting the lid so the dumplings steam through.