For the stock; I start by picking a Rotisserie chicken and tossing the carcass into a stock pot with a couple of chicken feet, chopped onion, celery, & carrots. Add in a few bay leaves and peppercorns. Add in a 6 cups of water and mark where the water is. Add more water to submerge and simmer for at least an hour and ideally 2-4 until you are down to the 6 cup mark. You will have to add water from time to time the longer you go. Strain out solids.
For the base; Dice a medium onion, 2 carrots, and 2 stalks of celery by hand or in a food processor. Saute in 2 Tbls olive oil and 2 Tbls butter over med low heat until almost tender. Add in 1/4c flour and stir for a minute to make a light roux. Begin adding the stock a cup at a time until incorporated and bring to a low simmer. Depending on my mood I may add a half cup of sherry as well. Season with salt, pepper, and thyme.
While that simmers make the dumplings. A food processor makes quick work of this. 2 cups all-purpose flour, 1 tablespoon baking powder, 1 teaspoon salt, 4 tbls cold butter thinly sliced and 4 tbls shortening, lard, schmaltz, or duck fat. (For herbed dumplings add in a little poultry seasoning, fresh parsley, and ground black pepper).
Pulse until it looks like sand with a few pebbles. Add cold buttermilk and pulse until it just comes together and is a little sticky. Roll out into a well floured surface to 1/4" thick. Use a pizza cutter to cut dumplings into squares. About 1"-1.5" Begin adding to the soup stirring well as you go. Use your eyes. You may have more dumplings than you need and keep in mind everything will thicken as it cooks. When it looks right, simmer for about 6-8 minutes to cook the dumplings. Fold in the shredded chicken and a few Tbls of chopped parsley