Brown Gravy

The recipe for brown gravy is adapted from The New McDougall Cookbook,
p.334.
BROWN GRAVY (makes 2 cups)
2 cups warm water
1 Tbs. onion powder
2 Tbs. cornstarch or arrowroot
3 Tbs. soy sauce (I used a "light" soy)
2-3 cloves garlic, pressed or 1/2 tsp. garlic powder (I used the powder,
thinking it would add some bulk to the gravy since I omitted the cashews)
1/8 tsp. freshly ground black pepper
1-2 Tbs. parsley flakes (optional)
*Place 1/2 cup warm water + all the ingredients except the parsley in a