I very regularly make chicken soup, leftover chicken, maybe cook down the roasted bones to make a broth, add whatever vegetables I have on hand. Some carrots, maybe some celery and onions, some fresh spinach, some frozen peas, anything I have on hand. I often have a carton of commercial chicken broth in the fridge, I add it to a lot of things, so if I have any of that, I add it in too. I recently found a really good biscuit recipe, King Arthur Flour's Cheddar and Black Pepper Biscuits. One night when I made soup and biscuits, I had some scraps left over and tossed them in the soup pot and found they made wonderful dumplings.What follows is a liberal adaptation of the recipe, as I cut a few corners.
I will assume you have your fairly brothy soup already made. I would guess you would want about a gallon or so, and a wider kettle will work better than a deeper narrow one.
1-1/2 c. all purpose flour
1 Tbl. baking powder
1/2 tsp baking soda
1 tsp salt
2 tsp. sugar
4 Tbl. softened butter
1/2 c grated cheddar
1 tsp course ground black pepper
1/3 c milk
In a large bowl, mix together all the dry ingredients and cut in the softened butter. You should do this like making a pie crust, you want it crumbly but not completely incorporated. You can do this with a pastry cutter or your fingers. Add the cheese and mix. Add milk and mix just until it holds together. Add more milk if needed, but this should be enough.
Pat or roll out on a lightly floured surface, until about 3/4 inch thick. Cut with a knife or pizza cutter into 1-1/2 inch squares. You should get about a dozen.
Bring soup to a moderate boil. Drop dumplings in, and stir carefully to make sure they all get into the broth. I would say it takes about 5 minutes or so until they get softened and moist. You can check them as you go along. Stir occasionally to make sure they all cook evenly and get into the broth evenly. One of the things the dumplings will do is add some thickening to your broth, so make sure you stir to the bottom every now and then to make sure you don't get anything sticking. Dumplings are done when they are soft and tender all the way through.
These could easily be converted to vegan, by using margarine instead of butter, omit or replace the cheese, and another liquid, like almond milk in the dough, and then just add to a nice vegetable broth soup.