The call from Mark Scarbrough's mother was the last straw -- and some inspiration for a new book.

She had a baking question for her son, co-author with Bruce Weinstein of almost 20 books about food. Did he know if the butter she was using to make cookies should be at room temperature?

The short answer to that evergreen question is no.

For years, Scarbrough and Weinstein -- cooking and food pros, James Beard Award nominees, online columnists for Weight Watchers -- have heard that question and other kitchen/food/cooking claptrap over and over (no, marinades do not tenderize meat).

Finally, they decided to stick a fork in these misconceptions all at once, with "Lobsters Scream When You Boil Them: And 100 Other Myths About Food and Cooking" (Gallery Books, $16), an informative and fun effort that tackles those half-truths and lies that have been taken as gospel by generations of cooks.

"Whenever we do our demonstrations or give classes, and no matter what we're teaching -- how to make paella, how to make gnocchi -- someone will ask, 'Why is it whenever I make cookies they're flat?' So I always ask, 'Do you keep your butter at room temperature?' Yes. That's why the cookies are flat. That question has become a touchstone."

The explanation is a combination of science and good old American marketing hype. Butter below 67 degrees stays solid, and in that state is better at holding air, which you need for better baked goods. If the butter's warm, it won't hold as much air, and your cookies are flat.

So why the myth about room-temp butter? Because room-temperature butter can be easily whipped by hand mixers, which came into vogue in the 1950s. Before that, kitchens had heavy stand mixers, which could handle the colder, more solid butter. Those puny little hand mixers would burn up under the stress, so we were told the butter had to be soft. Room-temperature soft. Voila, a myth was born.

Although the book dispels just more than 100 common myths with serious research, there were some findings that were hard to swallow.

Weinstein says he was surprised, for instance, to learn that, yes, you can refreeze meat.

"Researching it, talking to people at the FDA, you may compromise the texture, but you can refreeze it, as long as you take the right safety precautions," he says.

He still won't buy that you can roast a frozen turkey.

"Both Butterball and the USDA say you can," Weinstein adds. "Just remember to take that bag of giblets out after it's been in [the oven] for a while."

> Mythbusters

Never wash mushrooms; they're like sponges and will soak up water. We all know what mushrooms are grown in, right? Sometimes a paper towel or brush isn't enough to clean them. You can wash them. Depends on the type of mushroom.

Tear lettuce, never cut it with a knife because it browns quicker. Nonsense, say Weinstein and Scarbrough, who suggest you cut and tear two test samples and store them in the fridge. They'll turn brown at about the same rate, they say.

Keep the avocado pit in the guacamole to prevent it from turning brown. Sorry, but that browning is a chemical reaction that no pit will prevent or reverse. Better to make the guac right before you use it, keep it chilled, have some citrus (lemon or lime juice) in, and cover it, down to the surface, with plastic wrap.