Here is what I came up with after several tries:
1 whole chicken
1 onion, finely diced
2 small carrots, diced
2 stalks of celery, chopped
2 cloves of garlic smashed and minced
6 cups of water
1 tbsp olive oil
2 cups of all purpose flour
1 tsp baking powder
1 tsp salt
3/4 cup milk
First roast the chicken in 350 degree oven for 75 minutes:
Then debone and shred the chicken meat. Put a large pot on medium fire, heat up olive oil and sweat the onion with a small pinch of salt. When onion is translucent add celery and carrots, saute for 10 minutes before adding the garlic and saute for another minute. Add the chicken bone and water, simmer for at least one hour.
Mix the flour, salt, milk and baking powder and form a dough, roll it out into 1/4 inch thick and then cut into diamond shapes.
Remove the bones from the stock, skim off excess grease, and bring to a fast boil. Add half of the dumplings slowly, and then cover and bring to a boil again, before adding the second half. Add chicken meat, cover and simmer for 1 hour, with the last 10 minutes uncovered. Stir every 15 minutes or so or the dumplings might stick to the bottom. Add salt and pepper to taste. At the end, the soup should thicken from the flour on the dumplings. The baking powder helps making the dumplings very tender. Since you do not need to add roux to thicken the soup, no extra fat is added except the olive oil. For some reason the chicken meat doesn't get dry and tough after long boiling, as opposed to popular belief. It turns out tender, moist and still flavorful.