The safest choice for an LCer is a "Chicken Caesar salad - hold the croutons". You'll get a fairly plain piece of grilled chicken on a Caesar salad. Even if they bring the croutons, you can put them aside. You can even have bacon bits & extra Parmesan and still be quite a bit under the 20 grams.

Or how about a small steak with veggies instead of potatoes, or a burger (without the bun) and a salad?

Have lovely time.