To Prepare:

Snap the tip of one end of a bean with your fingers and draw it down the length of one side of the bean to remove any possible string. Do the same thing with the other end, pulling it down the other side of the bean.

Beans of not much more than 1/4 inch in diameter are cooked whole, and retain their maximum flavor. If they are large in circumference, you may slice them on the bias to make several 2 1/2-inch lengths per bean (this or machine slicing is usually called Frenched beans though it is rarely done in France as it is seldom necessary). Sliced beans never have the flavor of whole beans.

Wash the beans rapidly in very hot water the moment before cooking.

To Blanch:

Have ready a large bowl of ice water.

Bring 6 to 8 quarts of water to a boil in a large pot over medium-high heat. When the water is at a rolling boil, add 1 1/2 teaspoons of salt per quart of water, and drop in the prepared beans. Cover briefly, to bring the water quickly back to the boil, then immediately remove the cover. Boil uncovered until beans are just tender 2 to 3 minutes for smaller or frenched beans; 4 to 5 minutes for whole round beans. Taste test for doneness. They are done when they are just cooked through but still have the slightest crunch of texture.

Drain immediately, return the beans to the kettle and gently run cold water over them. When pot is half full, drain again. Transfer beans to the ice-water bath. The faster you chill the beans the greener and fresher they will remain. When thoroughly chilled, in 4 to 5 minutes, drain again. Set aside, or, if making in advance, dry them thoroughly and wrap in a clean dry towel and refrigerate in an airtight container or plastic bag (thoroughly chilled cooked green beans keep well for several hours).

To Finish or Reheat:

About 3 minutes before serving, in a large saucepan or skillet over medium-high heat, toss the beans to evaporate excess moisture. Add a piece of butter, salt and pepper to taste, tossing to combine. Add the rest of the butter gradually while tossing the beans; alternate with drops of lemon juice. Taste for seasoning. Turn into a vegetable serving dish, sprinkle with parsley, and serve immediately.