Just as potatoes don’t all look alike, neither do they cook alike. Starchy, dry potatoes like the russet or Idaho produce perfect fries and are excellent for baking. The russet is good for mashing, too, but the red-skinned, Yukon gold and yellow Finn—all somewhat less starchy—are even better. Steam thin-skinned new potatoes and use boiled waxy whites or reds for potato salad. Here are some additional tips:

--Cover whole or cut-up potatoes with cold water and bring to a boil before adding salt. (Salted water takes longer to boil.) To avoid the water boiling over, just partially cover the pan. Cook the potatoes at a brisk simmer.

--To test a boiled potato for doneness, insert a knife into the center. It should slide in easily, and the potato should slide off the knife easily.

--Parboil diced or sliced potatoes until they’re barely tender. Drain off the water, rinse the slices with cold water and dry them. Use them in recipes or simply pan-fry them in a mixture of half oil and half butter over medium-low heat until they’re brown and crusty.

--Mashed potatoes may be held warm in the top of a double boiler over gently simmering water.

--To enhance taste and nutrition, add some cooking water to mashed potatoes and subtract an equal amount of butter or cream.

--Never make mashed potatoes in a food processor. They become gluey when overmixed.