2 cups all-purpose flour

1 1/8 cups chopped walnuts (1/2 in dough, 1/2 topping)

1 12- to 14-ounce jar apricot jam or preserves

1. Preheat the oven to 350 F. Butter and flour a 9-by-13-inch baking dish.

2. In a medium bowl combine the butter and sugar. With an electric mixer on low speed, cream the ingredients together until well blended. Add the yolk and vanilla. Stir in the flour, mixing on low with the electric mixer until blended. Add the walnuts and mix until just blended together.

3. Divide the dough in half. Spread half of the dough in an even, thin layer on the bottom of the prepared dish. With a spoon spread the preserves evenly over the dough. With the remaining dough half, drop spoonfuls over the preserves, spreading across the top with a knife to the edges. You will have holes on the top; don't worry. Scatter the remaining walnuts on top.

4. Bake for 40 to 48 minutes, or until the bottom crust is light brown and the top is golden brown. Cool and slice into even bars with a serrated knife. Arrange on a platter and serve.

Recipe note: You can substitute strawberry, raspberry, pineapple or orange marmalade for the apricot preserves.

(Diane Rossen Worthington is an authority on new American cooking. She is the author of 18 cookbooks, including "Seriously Simple Parties," and a James Beard Award-winning radio show host. You can contact her at www.seriouslysimple.com.)