In a large heavy bottomed pot (like a dutch oven), melt butter over medium-high heat.
Add onion, carrots and celery. Cook for 5 minutes, until vegetables being to wilt. Add garlic and cook for 1 minute more.
Add flour and stir to combine. Cook for 1 minute.
Add evaporated milk and chicken stock and quickly stir to combine.
Bring to a boil and add chicken, thyme, black pepper and salt. Let soup simmer, uncovered, while you make dumplings.
In a large bowl, whisk together flour, baking powder, pepper, salt and thyme. Make a well in the center of the flour mixture and pour the milk and butter into the center of it.
Using a wooden spoon (or rubber spatula), stir together until dough ball forms. If your dough seems too dry, you can add an extra tablespoon of milk.
Using a large** sized cookie scoop, scoop dough and drop directly into the simmering soup. Place them around the pot, not all in the same place.
Once all dumplings have been added, gently press them down so the soup runs over just the tops of them.
Place the lid on your pot and lower the heat a little to a low simmer (you don’t want the bottom of the soup to burn but also want the soup to still be simmering to cook the dumplings).
Cook for 15 minutes, gently stir the soup/dumplings and then cut one dumpling in half to make sure they are cooked through.
If the dumplings are cooked through, serve hot! If not, cook an additional 2-3 minutes and check again.
*You can use a medium sized cookie scoop in place of a large cookie scoop to get more dumplings. Start checking if they are done around the 10 minute mark.