1. Find Out Dietary Needs in Advance
Guests who are vegetarian, vegan, or have specific food allergies will often let the host know in advance. However in a very large gathering, vegetarians especially may assume that there will be at least one meat-free option available. Nothing is more frustrating for someone who doesn't eat meat, or easier for a host to fix, than finding that every single dish in a dinner contains meat, fish, or poultry. With other less common special needs, the guest is more likely to let the host know.
It is impossible to plan for every possible dietary restriction. However, a small note at the bottom of an invitation asking guests to indicate special dietary needs, especially if RSVPs are required, is an easy way to ensure that there is at least something for everyone.
2. Serve a Wide Variety of Food
Variety is the best way to please not only those with dietary restrictions, but the diversity of palates that is inevitable at a gathering of any kind. If the menu is structured as a main dish, sides, and a salad, always consider offering two main dishes, and leave meat out of the second. Alternatively, offer a number of filling vegetarian side dishes, and consider serving one or two without dairy. Always try to have at least one vegetarian option aside from bread and salad.
Another easy way to accomplish variety is by serving a number of smaller dishes. Tapas, mezze, or antipasto all offer many things for many people. Potlucks are ideal for informal gatherings.
3. Keep the Food Simple
If you are cooking alone, especially, serving simple foods that require minimal preparation will take less time and reduce stress levels. Another advantage is that simple dishes are easy to recognize and less likely to contain foods that may be a problem. Also, if the individual dishes are simple, it will be easier to provide many options.
For example, try offering a variety of cheeses with fancy crackers or flatbread strips, a plate of fruit or raw vegetables, roast chicken, or sautéed vegetables with rice.
4. Prepare Familiar Dishes
When cooking to accommodate specific dietary needs, it is not necessary to prepare new, unfamiliar dishes (unless, of course, the host is looking for a challenge). Most cooks will find that they already have recipes in their repertoire that don't include meat, dairy, or flour. Vegetable dishes that include rice, beans, or another filling protein are often "safe" for everyone. Other dishes can be slightly altered by changing chicken broth to vegetable broth or omitting cheese. Gluten-free or vegan baking are not necessary for delicious desserts – try a simple vegan fudge or chocolate fondue with fruit for dipping. When in doubt, ask the guest what specific foods he or she cannot eat.
5. Use Labels
One easy way to avoid anxious guests and their embarrassment in having to question the host about the contents of each dish is to provide simple, tasteful labels for each item. A label should display the name of the dish and any ingredients that would be unexpected or are common allergens (such as nuts or shellfish). If an item is vegetarian, vegan, or gluten-free, the label should so indicate.