Your dish costs more than your recipe says

Yield loss is the big one

Buy a kilo of onions and you do not get a kilo of usable onion. Peel, trim and waste take a share before anything reaches a pan, and cooking takes more. Depending on the ingredient, the usable fraction can be well under three quarters of what was paid for.

A recipe written in usable weight and costed at purchase weight understates that ingredient by exactly the loss. On a dish built from three or four such ingredients the error compounds quietly.

Measure it once for your three highest-volume ingredients rather than using a figure from a textbook. It takes an hour and it is your kitchen's number, not somebody else's.

The costs that never make it onto the recipe card

• The accompaniments served with everything and costed with nothing.
• Packaging, which on a delivery order is a real per-order cost and is often larger than the margin on a side dish.
• Prep that was made and not used before it turned.
• The portion that goes out at 20% over spec because the person on the pass is generous and nobody has ever weighed it.

Weigh a portion during a real service

Not during a calm morning when someone is watching. Portion drift shows up under pressure, and it is almost always upward.

Weigh the same dish six times across a busy service. If the spread is more than about a tenth either way, the recipe cost is describing something the kitchen does not actually serve.

What to do with it

Cross-reference each dish's contribution against how often it sells. Dishes that do well on both should be the easiest things on the menu to find, and usually are not. Dishes that do badly on both should come off, and usually do not, because somebody is attached to them.

One exception worth protecting. A dish with poor margin that brings people through the door is doing a job the numbers cannot see. Cost it honestly, then keep it deliberately.