TIPS FROM FRENCH COOKS

The French have turned cooking tips into a veritable art. They have a tip, or truc, for just about every occasion. Patricia Wells's ``Bistro Cooking'' is sprinkled with hints to make the cook's life easier and more efficient. A sampling: Chef Jos'e Lampreia of Paris's Maison Blanche offers a suggestion for elegant, individual gratins: Prepare any gratin in individual nonstick ramekins or cake molds. Butter them lightly first, then bake. The presentation is prettier, and there's more crust - the best part - to go around.

A French grandmother's tip for more flavorful lentils: Add a teaspoon of vinegar and a sugar cube to the cooking water.

Salt does not dissolve in oil. Thus, when preparing a cold vinaigrette, always dissolve the salt in vinegar or lemon juice before whisking in the oil.

To prevent whole onions from breaking apart as they cook, peel them, make an incision in the form of a cross at the root end, then proceed with the recipe.

If herrings are too salty, soak them for about 3 hours in milk before proceeding with a recipe.

A tip for conserving leftover peeled garlic: Toss it in a bit of olive oil, cover securely, and refrigerate until you need it next. It will flavor the oil nicely, too.

Never add salt to eggs that have been whipped and will be incorporated with other ingredients. The salt will only liquify the beaten eggs.

Tiny clams, in particular, tend to be very sandy. To degorge them, or rid them of the sand, soak them for 1 to 2 hours in salt water, dissolving 1/2 cup coarse sea salt per quart of water.

How do you know if eggs are fresh? Place them in a bowl of cold, salted water. If they fall to the bottom and stay there, they're fresh enough to eat `a la coque, or soft-boiled.