If you want a restaurant to recognize someone’s birthday at your table, there is a proper way to ask. When you call to make a reservation, tell the receptionist that you’re celebrating in advance, or if you book online, make a note on your reservation. Birthdays are a nightly occurrence in every restaurant, so don’t expect any special treatment or a troupe of waiters to serenade you. Some restaurants have special routines for birthday guests, but most will simply offer add a candle in whatever dessert you order.
Most restaurants will not send a free birthday dessert, and you should never expect one. If possible, tell the maitre’d or host whose birthday it is when you check in or discreetly point them out to your server to avoid any confusion. Avoid waiting until the last minute, awkwardly beckoning the waiter to speak privately in plain view of the birthday boy or girl, and whispering instructions to orchestrate the “big surprise.”
Also, don’t feel the need to constantly remind the waiter that you’re celebrating a birthday every time they visit the table. If you want the celebration to go smoothly, communicate your instructions as clearly as possible, and they’ll take care of it. It’s best not to bring your own cake to a restaurant, but check with the restaurant in advance to see if they’ll allow it. Most fine dining establishments will likely levy a plating fee (as many do with wine corkage) if you insist on bringing your own cake. Restaurants need to sell food for a profit to survive, be respectful of that.