Fullsack wrote:Just purchased "The America's Test Kitchen Family Cookbook." An emergency substitution for 1 large egg is either: 1 jumbo egg, 1 extra large egg or 1 medium egg.

Lucky thing they mention that. I can imagine someone thinking, "I don't have the right size egg, I better put everything away and make something else."

FWIW, there are people who don't have much cooking/kitchen experience, and may tend to follow recipes verbatim. They follow the rules because they either aren't comfortable enough with the process, or don't understand enough of the interactions.

America's Test Kitchen (ATK) is an incredible reference; IMHO they are the standard bearers of providing accurate and reliable recipes and information for anyone from the stumbling tyro to the seasoned veteran chef. When they call out substitutions, the reasoning behind it is usually solid, accurate and well-researched.

With respect to your comment, the substitution may be negligible if the amount of overall moisture provided by a large egg is irrelevant, but if the egg is to be separated and used(e.g. yolk for emulsifying butter as part of a hollandaise, whites whipped separately and folded in later), then you have to consider whether the amount of lecithin in a large vs. jumbo/XL/med yolk will emulsify the prescribed amount of butter, or if the amount of butter needs to be reduced/increased to accommodate the substitution.

From my personal experience, I've been in the kitchen with someone who was following a recipe that called for 1/4 cup of diced onions. They had no onions, and were about to abandon the recipe. I checked the pantry and saw that there were plenty of shallots, and prepped them. Recipe turned out fine. Just some food for thought.

Can you tell that I've had the "change one variable at a time" thread in my head?

-s.