If restaurants weren’t cautious about food costs, many would go under, quickly. Food cost is the amount of a dish’s raw ingredients taken as a percentage of its sales price. If, for example, a whole fish costs $7 wholesale, and its accompaniments (say, garlic, white wine, and thyme) cost $1, the cost to the restaurant to make the dish is $8. The menu might list the fish for $24, which seems like a huge mark up, until you consider the labor (scaling, gutting, and cooking) in making it and potential waste (if not all of the fish sells in a timely fashion).

Each restaurant has different goals for its food costs, depending on its profit margin overall, and a bunch of other things. For some, food cost is as low as 20%; others, more like 30%. Often, higher end restaurants, while their menus are pricier, actually make less money per dish than more casual joints. For these expensive venues, experienced labor and premium ingredients, not to mention sometimes shameful waste, make food costs tally up quickly. In places serving the same daily burger and fries, however, where accountants formulate recipes alongside chefs, food costs are almost unfathomably low.

Food cost is important to all kinds of food service, of course. In many circumstances, chefs’ salaries are partially set by whether and how often they meet their food cost goals. Because food cost is a percentage of sales, one way to keep food costs low is to keep receipt totals high, something only a few restaurants can get away with. In these restaurants, for example, a fillet of fish may be trimmed of 25% of its weight in the interest of a perfectly symmetrical presentation (and perfectly even cooking). Attention to such detail–and, if the trim gets tossed in the trash, its consequential waste–is a hallmark of haute cuisine.

An arguably more reasonable way key of keeping food costs low is maximizing use. A chef can do this by incorporating leftover ingredients of one dish into another. Beet greens can be tossed with tagliatelle for an entree, while the root finds its way into a soup. Kitchen leftovers also make (often infamous) staff meals–a paillard of chicken goes to patrons; its liver and wings, to the cooks.

But there is a level of waste that is difficult even for restaurants to manage, and here, for once, scale–which otherwise favors a restaurant’s better buying power–works to the advantage of home cooks. When a bottle of wine sits with a half glass left, parts of a baguette dry out on a counter, and a 1/4 wedge of onion or a 1/2 an apple hide forgotten on a refrigerator shelf, a restaurant kitchen will as likely discard such items in an effort to make space (always an issue) and to keep their workspace tidy.

Of course, there are infamous and admirable chefs who rummage through trash cans next to their cooks’ prep stations. For most others, however, it is, in fact, a waste of time to think about these bit ingredients as players in off-the-cuff dishes (read: tonight’s special), especially if, at most, they yield enough to sell just one or two plates.

At home, we might have to be our own watchdogs, but we have real incentive to monitor the use of our scraps more diligently. We can do what restaurants can’t: make the little remains that sit in our refrigerator into creative nuggets of spontaneous, satisfying meals, just for ourselves and our modest table at home.

Here are a few small plates assembled from scraps. From the 1/4 bunch of parsley, 1/4 red onion, 1/2 lemon, chunk of couza squash, and half used container of ricotta cheese, I made:

A vinaigrette of chopped parsley, minced red onion, lemon, and olive oil, which I used to dress little potatoes

A crostini of zucchini slaw (couza squash, grated, and dressed with lemon and olive oil, salt) and ricotta

Tagliatelli with julienned zucchini, lemon zest, butter, and ricotta