Sauté the chopped onions with the olive oil, in a large soup pot for about 5 minutes over medium heat until just translucent. Add the carrots & celery, sauté another 5 minutes. Reserve 3/4 cup of cold broth for the dumplings if using the broth instead of the buttermilk. Pour in the broth and bring up to a simmer.
While the broth simmers, toss together the flour, baking soda, and salt. Combine the butter, lard or coconut oil, pressing it into the flour with a pastry blender, fork or your fingers.
When the butter is crumbled into pea size flour bits, stir in the buttermilk or broth. Form into a ball, knead only about 4-6 times on a floured surface. Press out flat, using a rolling pin, flat jar or wine bottle to roll it out. It should be about 1/4 inch thick.
Cut into strips, about 2-4 inches long and an inch wide to make big, fat fabulous noodles. Another cute option is to cut them into cookie cutter shapes! Drop each one into the simmering soup separately, to keep them from sticking together. Stir and continue to add to the pot until they are all cooking.
Finish by stirring in the frozen peas and shredded chicken. Bring back up to a simmer for about 5 minutes.
Serve immediately with a sprinkle of parsley if desired.
