No claims to authenticity with this recipe. I was super intrigued by the can of "duck" at the Chinese grocery and I made up a recipe to use it. The thick, tangy sauce goes well with the "meaty" duck substitute and eggplant. If you can't find the vegetarian duck at your grocery store, I'd substitute seitan since that appears to be the main ingredient in the vegetarian duck. Also, be warned that the recipe is kind of salty. If you prefer less-salty foods you could use less soy sauce (still adding water to make 3/4 cup) and be sure to rinse the "duck" extra well.