Mock chicken chow mein (made with seitan) doesn't take long to prepare, but it does require quite a bit of cooking.
Meals with a mixed group of vegetarians and non-vegetarians can require a lot of extra effort from the cook. However, you can save a lot of work by making similar dishes for both groups - a vegetarian version and a meat version. Here are some adaptable vegetarian recipes that lend themselves easily to meat additions.
Being a vegetarian or vegan doesn't mean you can never again make any recipes that call for things like beef broth, eggs, or gelatin. Most animal products can be replaced with vegetarian- and vegan-friendly ingredients.