Instead?

As with sources, cookbook writers have no obligation to suggest substitute ingredients, but blessings on those who do.

Sometimes a suggested substitute will appear in the ingredient list. In her recipe for Smoked Fish and Cider Pie (Pie, pp 73-73), Angela Boggiano calls for:

3 tbsp crème fraîche or sour cream

Even more helpful is telling us what kind of thing we're looking for and suggesting examples. The general description can come before or after the examples. In his recipe for Fresh Tomatillo Salsa (Mexican Everyday, pp. 152-153)Rick Bayless calls for:

hot green chiles to taste

and adds:

(I like 2 serranos or 1 jalapeño)

In his recipe for Spring-Dug Parsnip Chowder (50 Chowders, pp. 178-179), Jasper White calls for:

1 pound Yukon Gold, Maine, PEI or other all-purpose potatoes

Sometimes a suggestion about substitutes comes in a headnote, sidenote, or endnote. Cherie Y. Hamilton introduces her recipe for Rice with Limpets by telling us in the headnote:

Limpets are similar to small clams

and reinforces the information in the ingredient list:

2¼ pounds limpets or clams

Sometimes suggested substitutes can be found in a special section at the beginning or the end of the book.

blah blah

Ruling out a possible substitute can be just as important as suggesting one.

Wolfert on salted lemons

Sometimes an author won't go so far as to condemn a substitute but will make clear its inferiority. Fuchsia Dunlop's recipe for Aromatic Broth (Revolutionary Chinese Cookbook, pp. 54-55) calls for:

Shaoxing wine

There's no pointer from the recipe to the section on the Hunanese Pantry at the beginning of the book, but that section contains and entry for Shaoxing wine, and the index points to that entry. "Some Chinese cooking writers," says Dunlop, "recommend using medium-dry sherry as a substitute." It's hard to see how she could distance herself further from the recommendation without removing it altogether.

Fish is by far and away the ingredient that most cries out for advice on substitutes. Every time I've moved to a new place I've had to learn a whole new fish population and fish vocabulary. We really need for cookbook writers to tell us what characteristic will make a fish desirable in a recipe. Christine Manfield tell us in the ingredient list of her recipe for Grilled Fish with Harissa Dressing (Stir – love that title – pp. 36-37):

4 whole, plate-size fish (red snapper, rouget, catfish, cod, etc.)

Claudia Roden tells us in the headnote of her recipe for Deep-Fried Red Mullet with Garlic and Parsley (Arabesque, pp. 188-189):

Deep-frying is the most popular way of cooking small- to medium-size whole fish, and red mullet (barbunya) are among the most prized.

Angela Boggiano's recipe for Smoked Fish and Cider Pie (Pie, pp. 72-73) calls for both unsmoked and smoked haddock. What kind of a fish is haddock, oily or dry? Is it important that the unsmoked and smoked fish be the same kind of fish? Now again, I'm not saying that Boggiano is derelict. Pie is a British book for a British readership, and the British Isles may for all I know be awash in haddocks. There's no requirement that Boggiano explain herself to haddockless Americans. But she could endear herself to a larger audience by being more forthcoming.

Sometimes the suggestion of a substitute reveals a misunderstanding. Further down in the ingredient list of her recipe for Rice with Limpets, Cherie Hamilton calls for:

⅓ cup Madeira or other red wine

Rice with Limpets is a recipe from the Azores and Madeira. When Cherie says "Madeira" here she means red wine from Madeira, not the sweet, fortified dessert wine called Madeira (the thought of which sounded rather sickening with the clams and garlic).