Walnuts and apricots figure in Chinese feasts from antiquity. In addition to their culinary attributes, ground walnuts were favored as a remedy for baldness, and apricots were thought to cure disorders of the heart. Bald heads and faint hearts aside, most everyone will enjoy this moist and nubbly fruit and nut dessert, the creation of Berkeley chef Diane Dexter. It is a deep tart filled with a light mixture of crushed nuts on a thin base of orange and lemon-zested puréed apricots. It is a beautiful-looking dessert, dusted lightly with powdered sugar and adorned, if you wish, with crystalline, sugar-dipped walnut halves. The yin-yang blend of sweet-tart flavors and nut and fruit textures make it one of my favorite conclusions to a Chinese meal.
In the dry work bowl of a food processor fitted with the steel knife, process 1¼ cups walnuts until coarsely chopped. Filter through a sieve to obtain 2 tablespoons finely ground nuts for the crust, then put aside 1 cup chopped nuts for the filling. Do not fine-chop them at this time.
Return the steel knife and the 2 tablespoons ground nuts to the work bowl. Add the flour, sugar, and butter, then process to a paste, scraping down as necessary. Add the egg yolk, rum, and vanilla, and process with several on-off turns, just until the liquids are incorporated. Do not overprocess. Remove the dough from the work bowl and pat into a smooth ball.
Alternatively, blend the ground nuts, flour, sugar, and butter to a paste by hand. Beat the yolk, rum, and vanilla to combine, then add to the flour mixture and work lightly until smooth. Pat into a ball.
At this point, the dough may be refrigerated several days or frozen, wrapped in wax paper, then sealed airtight in a plastic bag. Bring to room temperature before shaping.
Press the dough into a 2-inch-deep removable-bottom tart pan 9 inches in diameter, or into a 9-inch springform pan. Use the same method, but make the bottom and sides of the tart evenly ⅛ inch thick. The walls should be a very even 2 inches high. When the crust is well shaped, use the tines of a fork or the blunt side of a knife to tap gently around the top of the crust to give it a pretty scored edge.
Refrigerate the crust for 1 hour or freeze it for 30 minutes before baking, loosely covered. To freeze it longer, wrap airtight once firm, and bake directly from the freezer.
Bake the crust until lightly browned, about 20 minutes. Turn once midway through baking to insure even browning. At the same time prick the bottom several times with the point of a knife if it has swollen in one or more bubbles.
Remove the crust to a rack to cool completely. It may be left at room temperature up to 12 hours before filling, and must be thoroughly cool when filled.
Put the dried apricots in a small, heavy saucepan. Add water to cover, then bring to a simmer. Cook uncovered over low heat until soft, stirring occasionally, about 10–15 minutes. Drain the apricots, retaining the liquids.
Add the apricots to the work bowl of a food processor fitted with the steel knife. Process until smooth, scraping down as necessary. Bit by bit, add enough of the cooking liquid to obtain a smooth, easily spreadable, jam-like consistency, processing after each addition to incorporate the liquid. Using the small holes on a hand grater, grate the orange and lemon zest directly into the work bowl on top of the purée, then process to blend. Be careful not to grate any of the white pith. Slowly add sugar to taste, processing to combine and tasting until you achieve the right balance of sparkly and tart tastes. Scrape the purée into a bowl to cool.
If you do not have a food processor make and season the purée in a blender.
Once cool, the apricot mixture may be refrigerated for up to 2 weeks, sealed airtight. Bring to room temperature before using. If the mixture has thickened, blend in a bit more water as needed to obtain an easily spreadable consistency.
Cream the sugar and butter in the work bowl of a food processor fitted with the steel knife, scraping down as needed until smooth. Add the yolks, and process to blend. Add the walnuts, vanilla, and rum, then process to combine until the nuts are peppercorn-size. Do not overprocess; the nuts should be nubbly. Scrape the filling into a bowl.
If you do not have a food processor, blend the filling in a mixer or by hand, chopping the nuts peppercorn-size before adding them to the bowl.
Put the warmed egg whites in a large, non-aluminum bowl with a pinch of salt, then whisk by hand until the whites form soft, thick peaks. Fold the beaten whites carefully into the walnut mixture until well incorporated. Use the filling promptly.
Bake until set, about 30–40 minutes, when a wooden skewer or the point of a sharp knife comes out clean when inserted into the center of the tart. Rotate the tart once midway through baking to insure even coloring.
When the center is firm and set, remove the tart to a rack to cool completely. Once entirely cool, remove the outer ring. Cover loosely, then let the tart stand at room temperature 12–14 hours before serving to allow the nut and fruit flavors to permeate the tart.
As much as 3 hours in advance of serving, dust the tart lightly with powdered sugar, entirely over the top or just around the edges, as you wish. If you are adding the crystalline walnuts, space them round side up evenly around the tart, about 1 inch in from the edge.
To serve, slip the tart still on its metal base onto a large serving platter, lined with a doily if you like. Do not remove the base, lest the fragile crust break. Present the tart whole, then slice it at the table, centering a walnut in each slice.
Leftovers keep beautifully for several days. Store at room temperature, loosely covered.
© 1982 Barbara Tropp estate. All rights reserved.