I'm afraid the gratin will take about 15 minutes to prepare, sir. Would you mind waiting?
Salt-Baked Chicken takes a long time to prepare. So you'd better order it in advance.
Roast Duck. There will be a slight delay for that.
The set menu will not take as much time.
Pizza will take about 10 minutes to prepare. Would you mind waiting?
Your order should take about 20 minutes, sir.
We'll try our best to serve you as soon as possible.
Your order will be with you very soon.
Your order will be ready in a minute.
The dish you ordered is coming immediately.
All right. All will be ready in a minute.
Your dishes will come at once.
It will be ready shortly.
I'll be back with your order in a little while.
I shall not keep you waiting long.