In a large, deep pot set over medium heat, add 1 tablespoon of olive oil. Once heated, add the chicken breast. Season with salt and pepper - to taste. Cook on each side 4-5 minutes, until internal temperature reaches 160 degrees F. Remove to plate, shred or cut into cubes and set aside.
Add 1 tablespoon of olive oil to the pot, followed by onions, carrots, and celery. Stir the mixture together, scraping along the bottom of the pan with a wooden spoon to remove any brown bits left from cooking the chicken. Cook 5-7 minutes. Add the minced garlic and saute for 1 minute.
Add the flour and cook for one minute, stirring to fully coat the vegetables. Pour in the stock and milk. While the liquid simmers, stir consistently until it starts to thicken.
Sprinkle in the seasonings: salt, pepper, bay leaves, onion powder, and thyme. Stir to mix. Cover and allow to simmer for 8-10 minutes. Add the chicken back to the pot to warm with the peas and corn. Remove the bay leaves. Give it a good stir and re-cover.
While that is simmering, combine ingredients for the dumplings into a medium bowl. First combine the flour, baking powder, salt, pepper, chives, parsley, and onion powder. Pour in the milk and stir slightly. Add the butter 1 tsp at a time or in small chunks. This will make it easier to cut the butter into the flour with a fork. Mix well.
Reduce the heat to low. Using a scooper, drop 2 tablespoon-sized balls into the soup. Batter should make 8 dumplings if using a 2-tablespoon scoop. Cover and allow the dumplings to firm up, approximately 10-12 minutes. The dumplings will increase to 2-3 times their size.
Season with salt and pepper, to taste. Serve immediately, garnished with dried chives and parsley.