I am beside myself that customers would think it OK to bring in their own cake. We sell dessert. If they insist, I tell them there will be a plate charge. Why do people think they can bring dessert to a restaurant? Is this common?
I don’t know how widespread this practice is, but it is definitely common enough that it is a question that has come up before and consistently frustrates restaurateurs, especially on busy nights where a large party consuming a dessert you did not sell prevents turning over multiple tables.
Like most problems, the root is a lack of communication that leads to a difference between expectations (“I have a great idea—I’ll bring a birthday cake to the restaurant.”) and reality (“What, I am not allowed to bring outside food and you charge me to bring my own cake? I had no idea!”)
You have a huge opportunity to set this right because of a key point you mention in your question: most of these guests have reservations. Too many restaurants think of reservations as one-way communication, from guest to restaurant requesting a table and the restaurant making a note of it. But a reservation is also an opportunity to make guests aware of your policies and expectations and even to make sales.
My advice is two-part:
- At the time of reservation, clearly communicate any policies that may potentially frustrate guests if they are not aware of them in advance: credit card, dress code, cancellation deadline and, most importantly in your case, that no outside food is allowed.
- Turn guests’ demand for cakes into a revenue-generating opportunity. At the time of the reservation, ask if there is a special occasion. Work with your staff or a wholesale bakery to offer special occasion cakes at a range of price points.
If a guest absolutely insists on BYOC, you will have communicated your policies, offered to supply the cake for them and can now inform them of the plate charge, all before they have even set foot in the restaurant. That communication should prevent heated discussions and frustrated people from spoiling a special occasion.