I found that using the amounts of red and black pepper given, the sauce tastes very spicy in the jar but much less so when added to vegetables, so use a little more red pepper flakes if you like a spicier stir-fry.
Saute the onion in a medium-sized sauce pan until it softens, about 4 minutes. Add the garlic and ginger and cook for another minute. Add the broth and continue cooking for another 5 minutes.
Spoon about half of the onions and broth into a blender. Cover and begin blending on low, increasing speed until mixture is smooth. Careful–it’s hot! Pour back into the saucepan. (If you prefer a smooth sauce, you can blend all of it.)
Add all ingredients except the sesame oil and cook on low until it reduces slightly, about 10-15 minutes. Add the sesame oil.
Add to “steam-fried” veggies at the end of cooking. I use about a cup of sauce for a large wok full of vegetables and seitan.
Half a teaspoon of dark (roasted) sesame oil gives the sauce a very light sesame flavor which, in my opinion, is essential to the flavor of the sauce. It also contributes about 1/4 of a gram of fat (about 2 calories) per serving. If you’d like, you can leave it out, or if you’d like a more pronounced sesame flavor, you can double or triple it and still have a sauce that contains less than a gram of fat.The exact amount of calories, fat, and sodium will depend on the vegetable broth used.The sauce should keep about two weeks in the refrigerator. Freeze it if you want to keep it longer.