Heat a large cast iron pot over medium heat. Once hot add the oil and onions to the pot and saute for a few minutes until the onions are soft. Then add the garlic and stir for a minute for the garlic to release it's flavor.
Now add the remaining ingredients- except the parsley. Stir to combine, place a lid on the pot and let cook for 20-25 minutes.
Taste the soup and add salt and pepper to taste.
Just before serving add the parsley. Serve hot and store any leftovers in the fridge.
If you don't have any Res El Hanout on hand you can mix up your own using this recipe.