In a large mixing bowl, combine the matzo ball mix, parsley, nutmeg, and 1 teaspoon of salt. In another small bowl, lightly beat the eggs with 1/3 cup of vegetable oil. Fold in the beaten eggs to the matzo ball mixture with a spatula. Add the sparkling water if you want the matzo balls fluffy, and mix well until well combine. Cover the mix and refrigerate for at least half an hour.
Bring about 12 cups of salted water to a rolling boil in a large soup pot. Bring heat down to medium and keep at a steady simmer. With wet hands, make about 1 inch balls out of the matzo ball mix and gently drop them into the water. Cover and simmer for about 25 to 30 minutes.
Meanwhile, heat a couple of tablespoons of oil over medium heat in a large cooking pot. Add the onion, garlic and chiles and sauté for 4 to 5 minutes until they have softened. Incorporate the sliced mushrooms. sprinkle the salt, stir and cover with a lid. Steam the mushrooms for about 6 to 8 minutes.
Take off the lid and pour the chicken broth over the mushroom base. Once it is simmering, incorporate the already cooked matzo balls, without their cooking liquid, and serve.