Prior to the unsettling news that eggs could be contaminated with salmonella, even before cholesterol became a concern, white sauces were viewed as the horse-and-buggy of thickened sauces. They were the "library paste" that bound tasteless chicken a la king or served as the basis for overly thick cream soups.

In reality they do not deserve this dowdy reputation, and any French cook worth his sel is as devoted to be'chamel and veloute' as hollandaise and mayonnaise.

The reason egg-emulsion sauces (hollandaise and mayonnaise) are potentially problematic is that it is almost impossible to heat the egg yolks to the magic, "safe" temperature of 160 degrees recommended for home cooks by the USDA without ruining the texture of the sauce. (FDA calls for 140 degrees for three minutes for food service professionals working under theoretically better controlled sanitary conditions.)

So flour-thickened sauces (be'chamel and veloute') are regaining popularity. When made with proper technique and proportions, white sauces are silky and light, especially if a combination of stock and milk are used.

Romancing the Roux The initial cooking of the butter and flour for a white roux is crucial to the success of the sauce, and its lack of a starchy taste.

Mastering this mysterious roux has been part of culinary training since the 17th century, when legendary Pierre Francois de La Varenne used the word in a cookbook. The name be'chamel for the resulting sauce was taken from noted 18th-century gourmand Louis de Bechameil, a courtier to Louis XIV.

Roux comes from the French word for red, and for many brown sauces the flour and butter is actually cooked to a nutty brown. For Louisiana gumbos, many recipes call for the oil and flour to be browned to a mahogany tone.

The more the roux is browned, the more will be needed to thicken a liquid. As is true with caramelized sugar, the carbohydrates are broken down and transformed during the browning reaction.

The cooking of flour with butter coats the starch granules, so the resulting sauce is far less likely to form lumps. And the proportion of flour to butter determines the consistency of the finished sauce. If you use about equal amounts, about 1 1/2 tablespoons of each per cup of liquid, you'll have a fairly standard sauce. Decrease the flour for a cream soup base; increase it for a souffle' base.

Once the flour and butter have been joined, stir them constantly over low heat with a wooden spoon for about two minutes, or until the mixture bubbles and is a rich buttery yellow without browning.

Simmering the Sauce Unless you have an urge to spend hours whisking, it's best to heat the liquid for your sauce in a saucepan or in a microwave oven. Slowly but steadily pour simmering liquid into the pan, whisking over medium heat until it comes to a boil.

It may start to get lumpy as it approaches the boiling point, but just keep whisking and it will smooth out.

Simmer it for at least two to three minutes, thinning it with more liquid if necessary to reach the right consistency. A cream sauce should be thick enough to coat the back of a wooden spoon.

While the amount of flour influences the viscosity of the sauce, the choice of liquid determines the richness. If heavy cream or extra butter is added, sure enough the sauce will be heavy and rich. I think whole milk is just about as rich as one could want a sauce, and that can be thinned with stock, if desired.

All white sauces will form a skin as they cool unless some steps are taken. The easiest remedy is to push a sheet of plastic wrap directly onto the surface of the sauce, and then you can forget about it. Alternatively, you can whisk it every few minutes.

Delicious Additions When turning a white sauce into a cheese sauce, wait until the sauce stops bubbling, and then stir in the grated or finely chopped cheese. For Swiss or cheddar cheese, 1/4 cup per cup of sauce is a standard measure, but if adding Parmesan, just a few tablespoons per cup will be sufficient.

For more flavor in either a white sauce or a cheese sauce, you can add some previously saute'ed chopped leeks or shallots, a pinch of herbs, or just about anything you want.

If Disaster Strikes Let's say you didn't cook the flour long enough, and the resulting sauce tastes pasty. There is nothing that can be done. Throw it out and start again.

But a few lumps are not reason for tears. Push the sauce through a sieve, and then whisk it again to a simmer over low heat.

BASIC WHITE SAUCE (Makes 2 cups)

2 tablespoons unsalted butter

3 tablespoons flour

1 1/2 cups hot milk

1/2 cup stock (or more milk)

1/2 teaspoon salt

1/4 teaspoon white pepper

1/2 cup finely grated cheese (Swiss or Cheddar), optional

Pinch of nutmeg, optional

1/4 cup saute'ed shallots or leeks, optional

Melt the butter in a saucepan over low heat. Add the flour and stir constantly over low heat for 2 minutes, or until the roux is bubbly but not colored.

Add the hot milk in a slow but steady stream, whisking constantly. Then whisk in the stock, salt and pepper, and bring to a boil over medium heat, stirring occasionally. Whisk until smooth, and simmer for 3 minutes over low heat.

If adding cheese, cool the sauce for a few minutes before stirring it in. Stir in any optional additions. Note: If making the sauce in advance, press a sheet of plastic wrap directly onto the surface to prevent a skin from forming.

Per 1/2-cup serving: 50 calories, 2 gm protein, 4 gm carbohydrates, 3 gm fat, 2 gm saturated fat, 9 mg cholesterol, 204 mg sodium.

Ellen Brown is a Washington- based food writer and prize-winning author of "The Gourmet Gazelle Cookbook."