To Make Ahead: Prepare the dough (Steps 2 and 3), cover and refrigerate for up to 1 day. Store the cookies in an airtight container at room temperature for up to 3 days. Roll in the second coating of confectioners' sugar just before serving.
Working on this makeover of a classic Russian Tea Cake made Bridget Klein feel closer to her late sister, Gina, because they are "a great match for her personality: delicate and refined, pretty to look at, and yet a definite character that inspires adoration and loyalty." Gina's middle name, Sarah, means "princess," in Hebrew; hence the name of these confections. Klein's mom "swore these cookies couldn't be made without butter," she says, "until she tasted them." Klein continues: "Gina was a traditionalist, too, but I think I might have been able to fool her with these."
Preheat oven to 400 degrees F.
Pour oil into a medium bowl. Whisk all-purpose flour, white whole-wheat flour, 1/4 cup confectioners' sugar, cornstarch and salt in another bowl.
Mix half the dry ingredients into the oil by spoonfuls. Scrape down the sides of the bowl and add vanilla. Mix in the remaining dry ingredients by spoonfuls until thoroughly combined. (The mixture will resemble creamed butter and brown sugar.) Stir in nuts.
Roll the dough into 1-inch balls; place about 1 inch apart on an ungreased baking sheet.
Bake the cookies until just set, being careful not to let the bottoms get too brown, 10 to 12 minutes. Cool on the pan for 2 minutes; transfer to a wire rack to cool slightly.
When the cookies are still warm, but no longer hot, roll them in the remaining 1 3/4 cups confectioners' sugar and place them back on the rack to continue cooling. (Reserve the sugar.) When the cookies are completely cool, roll them in the sugar again.
Per cookie: 105 calories; 7 g fat (0 g saturated fat, 4 g mono unsaturated fat); 0 mg cholesterol; 11 g carbohydrates; 1 g protein; 1 g fiber; 8 mg sodium; 19 mg potassium