Mayonnaise
Getty ImagesFood writer Michael Ruhlman's book, Ratio, might just free you from cookbooks forever. Instead of relying on recipes, Ruhlman breaks down cooking into easy-to-understand ratios of ingredients, a method he says allows for more creativity in the kitchen. "When you know a ratio, you don't know a single recipe, you know a thousand," he says. Once you've mastered the basics, you're free to start experimenting by adding or subtracting flavors.

MAYONNAISE RATIO: 20 parts oil: 1 part water (plus yolk)

It's a staple on BLTs, and your burger wouldn't be the same without it. But Ruhlman insists mayonnaise is much more than a decadent sandwich spread. "It's a sauce," he says. "There's just no end to what you can do with it. "

At its most basic, mayonnaise is a creamy emulsification of oil and water, bonded together by a rich yellow egg yolk. Using Ruhlman's ratio, making this flavorful sauce is simply a matter of slowly whisking together 20 parts oil to one part water. Acidity in the form of lemon juice is a common addition, but the star of the show is really the egg yolk.

"A yolk has not only richness and fat, which give a mayonnaise some flavor and color, but it also contains a chemical called lecithin, which is an emulsifier," Ruhlman explains. Whisking creates billions of oil droplets, each separated by thin sheets of the water. Lecithin, which is both fat- and water-soluble, helps both ingredients play nicely, creating a creamy, opaque sauce.

"It's really a miracle," he says. "You wouldn't want to eat a spoonful of vegetable oil, but you transform it with a little technique into something extraordinary. That's what cooking is all about: Great transformation."

As with all of Ruhlman's ratios, this one is meant to be flexible. Add shallot or garlic for flavor. Substitute white or red vinegar for the lemon juice. Stir in fresh herbs like dill, basil or chives. "My favorite mayo is made by adding some lemon juice and shallot. It's an extraordinary dipping sauce for asparagus or steamed artichoke -- really any green vegetable," he says.

He refutes the myth that mayo can be temperamental. "It's not that hard," he says. "You don't need to stand there whisking it for hours. It's not a labor intensive process." And if you do find yourself with a broken sauce, there's an easy fix, he says. Just grab a new bowl, add a teaspoon of water, and slowly whisk in the broken mayo. No problem.

Once you've made a batch, please don't skimp. "We have been trained to fear fat," says Ruhlman. But every chef that you talk to will tell you the same thing: Don't be afraid of fat. Fat doesn't make us fat -- eating too much makes us fat. Fat and acidity are two main components of why a dish tastes good or does not taste good. So you need to learn to use fat well."

And please, he says, steer clear of the tubs of store-bought brands. "Homemade mayonnaise has a texture that is glorious and sublime," he rhapsodizes. "The flavor is fresh, clean, and delicious."

From RATIO: THE SIMPLE CODES BEHIND THE CRAFT OF EVERYDAY COOKING by Michael Ruhlman. Copyright 2009 by Ruhlman. Reprinted by permission of Scribner, a Division of Simon & Schuster, Inc.