An occasional series in which staff members share a recipe that we turn to time and again:

Edith Eis is one of those friends of the family who seem closer than some blood relatives.

She and my mother, Anne Kramer, shared an apartment together after coming to this country from Germany, my mother in 1939 and Edith a year later. They had been classmates at a school outside of Munich. Reunited in Chicago, not knowing what had become of their families left behind, they became friends for life.

As a kid, our families got together too many times to count. No special occasion was necessary. We spent holidays together, too, except for Thanksgiving, which we had to share with our own extended families. (Here's what I mean about being closer than some relatives: Growing up, I would get modest birthday checks from relatives with a note to "get something you want." Edith knew to get a baseball for my charm bracelet.)

Long before instant messaging, Edith and my mother were in constant contact.

Of the two, Edith, now 84, was the baker. My mother made a mean cream puff, but even she would attest to Edith's baking prowess. My favorite is her plum cake.

She has been making it since 1946. Her mother made it before her. The recipe came from a Bavarian cookbook, which called it a zwetschgen kuchen, or plum cake. Because it's so shallow, I think of it as more of a tart. When Marian Burros reprints a similar recipe in the New York Times, it's a torte.

Whatever you call it, the important thing is to wait until Italian prune plums are available, near the end of the plum season. (They're in some supermarkets now, but they won't be around for long.) Prune plums are best for baking. They're purple-skinned and small -- golf ball-size but oval -- and the pit lifts out easily. The flesh is yellowish-green; it's juicy, yet firm enough to keep its shape when baked.

The crust needs to be thin, no more than 1/4 inch. While most plum cake recipes call for sprinkling sugar and cinnamon on top, Edith likes to toss the fruit with the cinnamon sugar to get more coverage. And when placing the plum slices in the pie shell, she says to be sure to overlap them. "That way you get a juicier cake," she says. For a 9-inch cake, you'll need 16 prune plums -- no more, no less.

When we spoke the other day, Edith had already made two plum cakes this season and was preparing to make another.

Edith's Plum Cake

8 servings

Served with vanilla ice cream, it's memorable.

11/3 cups flour

51/3 tablespoons cold unsalted butter, cut into pieces

5 tablespoons sugar

1 egg, beaten

Grated zest from 1/2 lemon (about 11/2 teaspoons)

1 tablespoon ice water

16 prune plums (1 to 11/4 pounds)

1/2 teaspoon cinnamon

1/3 cup pecans, ground

In a medium bowl, mix the flour and butter until well blended. Add 2 tablespoons of the sugar, the egg, grated lemon rind and the ice water and mix until well combined. Shape the dough into a disk, wrap in plastic wrap and refrigerate for at least an hour.

Have ready an ungreased 9-inch springform pan or tart pan. Using your fingers, press a 1/4-inch thick layer of dough into the pan and about 1/2 inch up the sides. Cover the pan loosely and refrigerate while preparing the filling.

Preheat the oven to 375 degrees.

Slice the plums lengthwise into quarters, removing the pit, and place them in a medium-size bowl. Add the remaining 3 tablespoons of sugar and the cinnamon and toss to coat the fruit evenly.

Scatter the ground pecans on the unbaked pie shell. Starting with the outer edge, overlap the plum quarters in circles, with the cut sides up. Bake 45 minutes or until golden brown. Let cool to room temperature.

Per serving: 255 calories, 4 g protein, 34 g carbohydrates, 12 g fat, 48 mg cholesterol, 6 g saturated fat, 10 mg sodium, 2 g dietary fiber

Recipe tested by Marcia Kramer; e-mail questions to food@washpost.com

-- Marcia Kramer