1. In a medium pot, heat the olive oil over medium heat and sauté the diced onion, carrots, and celery until they begin to soften.
2. Add the diced chicken breast to the pot, seasoning with half of the salt and pepper, and cook until the exterior is no longer pink.
3. Pour in the chicken bone broth and bring the mixture to a gentle simmer.
4. In a small bowl, whisk together the oat flour, baking powder, dried thyme, dried parsley, and the remaining salt and pepper.
5. Stir the Greek yogurt into the dry ingredients until a thick, tacky dough forms.
6. Use a small spoon to drop golf-ball-sized portions of the dough onto the surface of the simmering broth.
7. Cover the pot with a tight-fitting lid and steam for 10-12 minutes until the dumplings are puffed and cooked through.
8. Garnish with fresh parsley and serve warm in a shallow bowl.