PHILIPPA MONSARRAT may be the best cooking teacher in Canada. She accepts only eight student-disciples at a time to work in the kitchen of her cottage on tree-shaded, suburban Poplar Street in Halifax, Nova Scotia. This location is hardly at the center of modern Canada, yet aspiring students fill her classes a year in advance. I, too, made the pilgrimage.

"Anyone can learn the mechanical side of cooking - even the problems of puff pastry - reasonably quickly. Translating a good recipe into a reality in the oven is nothing. What I try to give them that is really important is, first, the habit of applying an analytical mind to every process, however small, to find the most efficient way of doing it and, second, I try to send them away from here with a large measure of self-confidence." So said Monsarrat, who is nothing if not a redoubtable personality with an English accent laid on so thick you can cut it with a butter-knife.

One of her disciples told me:

"She also teaches you - and this is the most wonderful thing I can find about her - the art of taste. She trains the tip of your tongue as much as she developes the skill of your fingers and alertness of your mind."

Above all, she brings an experimental approach to all her recipes. Her Irish stew is so beautifully organized for easy and fast preparation that it would be perfectly logical to baptize it "instant Irish." One of her desserts is titled Hasty Creme Brulee. And then there is her fantastic sauce hollandaise. But before she let me in on the secret, she told me something about herself.

She was born in Johannesburg, South Africa, with, youmight say, a golden spoon in her mouth. Her father was in gold mining. Once a year, the children were allowed to stir the Christmas pudding and make a wish. That was the full extent of Philippa's early gastronomic training.

When she had completed her education, she made the grand tour of Europe, living and studying in Germany, Italy, Austria and France. There she developed a passionate interest in food and its preparation.

"Often, I would be taken to dinner at a fancy restaurant by some young man and then he would just lose me. I would become involved with the chef, who would invite me into his kitchen, where I stayed and watched and helped and tasted for the rest of the evening. Finally, the young man simply had to pay the check and go home alone."

A few years later, she met and married the brilliant young British diplomat and author, Nicholas Monsarrat (most famous for his novels, "The Cruel Sea" and "Tribe That Lost Its Head"). They traveled in diplomatic circles around the world. "I guess I tasted every dish known to civilized dining - every variation of caviar and pheasant under glass," she said. Monsarrat was appointed to the British Embassy in Ottawa, where his wife polished her culinary skills with diplomatic dinner parties in their big house, but the pressures of diplomacy and her husband's growing fame as an author were too much for them and their marriage ended.

"Taking my two young sons and my dog under my arms, I shook the dust of Ottawa from my feet, lived for a while in Montreal and Toronto, and fell in love with the beautiful seacoast and marvelous fishy products, as well as the farm goods and eggs, of Nova Scotia."

That brings us back to her revolutionary hollandaise.

This famous and universally used sauce (invented by French Huguenots while refugees in Holland during the time of persecution by King Louis XIV) is really just a very tricky way of gently cooking egg yolks in butter with so little heat and such beating that the eggs don't scramble, but form a creamy, unctuous sauce.

It's a fairly delicate operation that can be done very quickly in an electric blender or food processor, but the texture of the super-fast hollandaise is quite different from the old-fashioned real thing. It is denser and heavier. Much less air is beaten in. The lightness is missing. To get it right, you must - as one famous chef wrote in an article - "use a double boiler and incorporate the butter into the egg yolks in such a way as to avoid scrambling the eggs." This has always involved about 20 minutes of continuous, slow stirring, while adding the butter one piece at a time. The whole job seldom took less than 30 or 40 minutes.

"Nonsense!" says Monsarrat. Instead, she uses a heavy, cast-iron, enameled frypan and puts all the butter and all the eggs and all the other ingredients in at once. Her secret is to make sure that everything is quite cold, so that as the butter slowly melts, it very slowly blends with the eggs. But slowly, for this recipe, means somewhere between 3 and 5 minutes!

Frankly, when she gave me her recipe, I didn't think it could possibly work. It was just too simple to be believable. But as the transformation took place with magical certainty under my hands and I realized that the method was virtually fail-proof and foolproof, all of us watching in the kitchen were amazed not only by the certainty and efficiency of the method, but also by the pure excellence of the finished sauce. If you precisely follow the instructions below, you will be equally amazed.

PHILIPPA MONSARRAT'S 5-MINUTE HOLLANDAISE

(Makes about 2 cups) 13 tablespoons very cold unsalted butter, cut up Up to 2 teaspoons freshly-squeezed lemon juice Up to 2 teaspoons top quality white wine vinegar 3 large egg yolks, lightly beaten with a fork Salt and freshly ground pepper, to taste

Kitchen equipment: Heavy 10-ich frypan or saute pan of material that does not conduct heat too quickly (not copper, but ideally enameled cast-iron), well-balanced balloon wire whisk, small mixing bowl for egg yolks; 2 chilled dinner plates.

Once you start, you must work continuously and quickly and all the ingredients must be kept quite cold. That is the trick. Also, your frypan must not be warm; it must start at room temperature.

Take the 2 dinner plates out of the freezer. Cut the butter into pieces about 1/2 tablespoon each and place each piece, as it is cut, on an ice-cold dinner plate. When the pieces of butter are spread across the plate, cover it with the second plate, upside down and place both in the coldest part of the refrigerator, but not in the freezer.

Prepare the remaining ingredients. Mix together 1 teaspoon of lemon juice and 1 teaspoon of vinegar. Lightly beat the yolks with a fork. If there is to be any delay, even of 2 to 3 minutes, before you begin, each of the above ingredients should be held cold in the refrigerator. Finally, have near at hand a salt shaker and pepper grinder.

Now, ready, set, go!

Put everything into the frypan: butter, lemon juice, vinegar and yolks. Sprinkle, to your taste, with salt and pepper. Set the frypan, at once, on medium-low heat. Arming yourself with the wire whisk, immediately start stirring the ingredients together and lightly scraping the frypan. Never stop. More back and forth and all around. If lumps of butter stick in your whisk, shake them out.

It's a good idea to have a timing clock. After about 2 minutes, if the heat is about right, the butter will begin melting and blending with the yolks and the sauce will begin to form and thicken. Now, while continuing to scrape and stir, also start beating, to fluff the sauce by trapping air in it. By 3 minutes, the sauce should have the thickness of heavy cream. As you approach 4 minutes, it may show signs of becoming too thick. If there is too much thickness, beat in 2 or 3 drops of cold water. This not only thins it, but also reduces the temperature.A hollandaise should never get too hot, never more than lukewarm.

As you aproach the 5-minute perfection mark, taste the sauce and adjust its flavor to your liking, beating in, as you please, a drop or two more lemon juice, vinegar, salt, pepper. The moment it is done, remove it from the frypan to avoid overcooking, and transfer it to warm sauceboat, in which it can be kept lukewarm, covered, until ready to serve.

This sauce keeps perfectly in the refrigerator about one week and be gently reheated.

Working notes - Variation for bearnaise sauce:

You can make a beanaise sauce by this same quick method. Reduce the amount of butter to 10 tablespoons. Increase the egg yolks to 4. Instead of lemon juice and vinegar mixture, prepare, about half an hour in advance (to give it time to cool down), a tarragon essence, as follows:

Put into small saucepan 5 tablespoons of young, fairly sharp, white wine, plus 2 tablespoons of good tarragon wine vinegar, 2 peeled and finely-minced shallots, and 1 teaspoon of freshly squeezed lemon juice. Boil to reduce it to just about 2 tablespoons of liquid. Then strain out the solid shallots, squeezing them in the sieve to extract every drop of juice. Add to the remaining liquid 2 or 3 drops of cold water to cool it.

As soon as the tarragon essence is cool enough, proceed directly as in the hollandaise recipe. At the last moment, if it is the season, blend into the sauce a couple of tablespoons of finely chopped fresh tarragon leaves. Dried tarragon is impossible, it tastes like hard sand in the sauce. CAPTION: Illustration, no caption