I can count all of the vegetarian Vietnamese restaurants in our county using one hand. There's Au Lac, Thuyen Vien, Bo De Tinh Tam Chay, Zen Vegetarian Restaurant, and Hoa Sen Vegetarian Restaurant.
With the opening of Vegan Cuisine, it seems I'll have to use the other hand. If I'm not mistaken, it is the county's sixth vegetarian Vietnamese restaurant.
And it not only seems to do Vietnamese staples like pho in a vegetable broth, but also spaghetti with soy meatballs in tomato sauce, and even lasagna.
11743 Edinger Ave., Fountain Valley, CA 92708, (714) 839-8305