Heat the olive oil in a medium pot over medium heat until shimmering.
Add the diced yellow onion, carrots, and celery to the pot, sautéing for 5 minutes until the vegetables are softened and fragrant.
Stir in the diced chicken breast, sea salt, black pepper, and dried thyme, cooking for 3-4 minutes until the chicken is opaque on the outside.
Pour in the chicken broth and bring the liquid to a gentle boil, then reduce the heat to maintain a steady simmer.
While the soup simmers, whisk together the whole wheat flour, baking powder, and chopped parsley in a small mixing bowl.
Stir the Greek yogurt and water into the flour mixture until a tacky, soft dough forms, being careful not to overmix.
Scoop the dough by the tablespoon and drop carefully into the simmering broth, spaced apart.
Cover the pot with a tight-fitting lid and cook for 12 minutes without lifting the lid, allowing the dumplings to steam until fluffy and cooked through.