1/2pound unsalted butter
1 1/2 cups sugar
Pinch of salt
1 egg yolk
2 1/2 cups flour
1 cup blackberry jam
1/2 cup egg whites
1 teaspoon lemon extract
3/4cup grated walnuts
1 cup chopped walnuts
1.Preheat the oven to 350 degrees. In a mixer fitted with a paddle attachment, cream the butter, 1/2 cup of the sugar and the salt. Mix in the egg yolk, then the flour until just combined. (The dough will still be crumbly.) Transfer to an 11 1/2-inch-by-16. 1/2-inch baking sheet and, with floured hands, press into a thin, even layer, covering the pan. Spread the jam evenly over the dough.
2.In a mixer, whisk the egg whites until they form soft peaks. Gradually add the remaining cup of sugar and the lemon extract and mix until a stiff-peaked meringue forms. Fold in the grated walnuts. Swirl the meringue over the jam-covered dough. Sprinkle with chopped walnuts. Bake until the meringue is hardened, 35 to 40 minutes.
3.Cut the cookies in the pan while still warm, 8 rows by 11 rows. Lightly press the broken meringue into the jam layer. Set the sheets on cooling racks. Makes about 7 dozen cookies. Adapted from Sunset Magazine, 1958.