To prepare the soup, heat oil in a heavy stockpot or large saucepan over medium-high heat.

Season chicken with salt and pepper then arrange in pot in a single layer and cook until first side is golden brown, about 3 minutes.

Turn chicken over, add onions and continue to cook until chicken is golden brown all over and onions are tender, 3 to 4 minutes more.

Add broth, thyme and bay leaf then cover, reduce heat to low and cook until chicken is tender and meat pulls away from the bone, 25 to 30 minutes.

With a slotted spoon, transfer chicken to a plate and allow to cool.

When chicken is cool enough to handle, remove meat from the bones and cut into bite-size pieces; discard bones.

Meanwhile, add carrots and celery to the pot and stir to combine.

Cover and cook for 10 minutes over medium heat, or until just tender.

Return meat to pot along with peas and parsley and bring to a simmer.

To prepare the dumplings, put rice flour, fava bean flour, tapioca flour, baking powder, thyme and salt into a bowl and whisk together until blended.

Add margarine and crumble the mixture with your fingers until it resembles coarse meal.

Using your hands, work quickly to mix in egg and 1 tablespoon at a time of the milk until the dough forms a shaggy ball. Be sure not to overwork the dough, mixing it just until it comes together but isn't too wet.

Using a tablespoon, dip the spoon into the soup, then dip the spoon into the dumpling batter to fill the spoon.

Drop it into the slow simmering liquid.

Repeat the process until you've used all of the batter to make 12 dumplings. (Cook dumplings in two batches if necessary to avoid overcrowding the pot.)

Once the dumplings are in the simmering liquid, cover the pot immediately and simmer for 10 minutes, resisting the urge to look inside the pot.

Ladle chicken and dumplings into bowls and serve hot.