ALL THOSE new-bride jokes aside, don't start your beloved's cooking lessons with boiling water. Any lover worth his salt is bright enough to master filter coffee and the two-minute egg on his own.

But sauteed onions and mushrooms are the Dick and Jane of the culinary primer, and once mastered can smooth the way for your Signigicant Other's first entree into gracious society. As a matter of fact, they have to be mastered: The scent and sting of uncooked onion can ruin the fanciest of sauces, and may curl the edges of your intime affections as well.

The onion is the produce world's metaphor for love. Over a period of several meals, introduce your SO to the various members of the onion family: the bigger bulbs, white, yellow and red; scallions and spring onions; chives and shallots. The range of pungency and bite (have him taste each raw and then gentled) is likely to surprise him, but will also encourage him to experiment once he strikes out on his own.

The most commonly misused is the house-and-garden variety bulb, either white or mesh-bag yellow. I much prefer the texture and flavor of the whites, but it's a personal matter.

For his first and basic batch of sauteed onions, assemble butter, dry vermouth (in cooking, "vermouth" means the dry -- white-- variety unless sweet red vermouth is specified) or white wine, basil or parsley or some Salt may be necessary if the butter is unsalted, but most "sweet" butter is lightly salted and the vermouth is seasoned. The presence of pepper depends on the dish. Also have ready a lemon quarter or a bottle of lemon juice.

First, chop the onions. Here's the Child method, more or less: Pull off the dry, parchment outer layer. Cut one "pole" of the onion off, and take hold of the other knotty end. Holding the knife horizontally, make parallel cuts from the cut end toward your hand, but do not slice all the way over to to the pole. Then turn the knife so the blade is pointing toward the pole, and make several downward cuts, again not quite all the way over. Finally, point the blade away from you , in the usual manner, and begin slicing the onion. The dices will fall away free -- theoretically, anyway. With a little practice, this can be a fast production.

Here's a more vulgar method, probably slower but apparently instinctive: Peel and slice the onion, then lay the slices flat and chop across them first one way and then the other.

Whichever, now that the onions are ready melt a tablespoon or so of butter over medium heat until the foam rises and then falls away. Scrape in the onions and either turn with a spoon or shake so that all pieces are oiled. Simmer for a minute until the onions begin to clear (don't let them stick or burn), then splash with vermouth and sprinkle with the seasoning. Simmer another moment unitl the wine evaporates.

Now let him taste. Amazing, isn't it? Like silk from a sow's ear.(The lemon juice , incidentally, is to obliterate the history of the onion's transmogrification from your fingers.)

You might as well take this opportunity to slip in a short course in garlic cloves, which will be sauteed with the onions in the vast majority of cases. The skin from a clove of garlic can be removed by cutting away the hard corners and peeling, or by smashing with the flat blade of the knife so that the skin splits. Then chop. Lemon juice works on garlic, too.

The main trick to mushrooms is cleaning them without diluting the flavor or letting them get soggy. Either rinse them under gently running water, smoothing the dirt away with your fingers, or wipe with a wet paper towel. Let them air dry for a few minutes, and trim away the bottom of the stem if necessary before slicing.

The easiest way for your beginning chef to finish his first skillet venture would be to scramble eggs over the onions, but you could dare him to try a simple chicken or veal. For instance, scrape the vegetables to one side, briefly brown two chicken breasts and splash in a bit more vermouth and basil, salt and pepper (you might also let him experiment with the various-colored peppers). Simmer gently just until it thickens and then pour over the meat.

Now, you make impressed noises -- after all, this is his first dish. It's going to be a fare to remember.

Next week: Common culinary crises and elementary rescue operations.