Heat the oil in a large pot over medium low heat, then add your onions, celery, carrots and garlic, and cook until tender for about 5 minutes, stirring occasionally.
Add the stock to your pot, clamp a lid on, crank up the heat to bring it to a boil, then lower the heat to simmer for about 10 minutes.
While your vegetables are simmering, mix up your dumpling dough. Add the flour, baking powder, baking soda, salt, pepper, sage, and mustard powder to a large mixing bowl and whisk them gently to combine everything.
Add the cold butter and lard, and use your fingers to mix this together until you have a coarse, shaggy mixture.
Stir your buttermilk into your dry ingredients quickly but gently so you don't overmix and have tough dumplings.
Use your cookie scoop or a soup spoon to scoop out your dumpling dough. You can form them into a ball first or add them straight off the scoop gently into your simmering soup pot. You'll have about 12 dumplings.
Put the lid back on the pot and let the dumplings cook for about 10 minutes over medium low heat.
Add your chicken to the pot, and stir it through gently to distribute the chicken, but try not to bust your tender dumplings.
Let this all simmer together for about five minutes.
Check your seasonings, then serve piping hot to people you think are awesome.
