BY YOTAM OTTOLENGHI AND HELEN GOH
These sandwich cookies from Yotam Ottolenghi and Helen Goh’s Sweet turn a classic Australian dessert into a soft, buttery vessel for bubblegumpink rhubarb icing, sharpened with a bit of lemon. The dough’s secret ingredient is custard powder— an instant pudding mix that does triple duty here, lending the cookie structure, a sunny yellow color, and a soft, pleasantly artificial vanilla flavor.
MAKES 15 COOKIE SANDWICHES
1 1/3 cups plus 2 teaspoons all-purpose flour, plus 1 tablespoon for dusting
1/2 cup custard powder (or cornstarch)
1/2 cup plus 1 tablespoon confectioners’ sugar
1/8 teaspoon salt
3/4 cup unsalted butter, at room temperature, cubed
¼ teaspoon vanilla extract (or ½ teaspoon, if using cornstarch)
1 small stalk of rhubarb, trimmed, washed, and cut into 1-inch/3-cm lengths
4 1/2 tablespoons unsalted butter, at room temperature, cubed
1 cup plus 2 tablespoons confectioners’ sugar
½ teaspoon lemon juice
1. Preheat the oven to 350°F/180°C. Line a small baking sheet with parchment paper.
2. To make the rhubarb icing, spread the rhubarb out on the lined baking sheet and roast it for 30 minutes, or until softened. Remove from the oven and allow to cool before transferring to the small bowl of a food processor. Process to a puree, then add the butter. Sift in the confectioners’ sugar, add the lemon juice, and continue to process for a couple of minutes; it seems like a long time, but you want it to thicken, which it will do as it’s whipped. Transfer to a small bowl and chill in the fridge for a couple of hours to firm up. (You don’t want the icing to be at all runny, so add a little more confectioners’ sugar if necessary; it needs to hold when sandwiched between the cookies.) The icing can be made up to 2 days in advance and kept in the fridge.
3. To make the dough, sift the flour, custard powder (or cornstarch), confectioners’ sugar, and salt into the bowl of an electric mixer with the paddle attachment in place. Beat on low speed to combine. Add the butter and continue to beat on low speed until the mixture resembles breadcrumbs. Add the vanilla extract, increase the speed to medium, and beat for about 30 seconds, until the dough comes together.
4. Line two baking sheets with parchment paper.
5. Pinch off small bits of dough and use your hands to roll them into 1 1/8-inch round balls; you should have enough dough for 30 balls, about 1/2 oz each.
6. Place dough balls on the lined baking sheets, spaced about 1 1/2 inches/4 cm apart. Dip the back prongs of a small fork in the remaining 1 tablespoon flour before gently but firmly pressing down into the middle of each cookie. The balls will increase to about 1 1/3 inches wide, but don’t press all the way to the bottom; you just want to create firm lines in the dough rather than force them to spread out.
7. Bake for 25 minutes, rotating the sheets halfway through, until the cookies are dry on the bottom but have not taken on too much color. They will be relatively fragile when warm but still firm to the touch. Set aside on the baking sheets to cool for 5 minutes before transferring to a wire rack to cool completely.
8. Sandwich pairs of cookies together with the icing, with the “forked” sides facing outward. You should use about 1/2 oz/15 g of icing in each cookie sandwich. It will seem like a lot, but trust us—the cookies can take it. Once assembled, the Yo-Yos can be kept for up to 5 days in an airtight container, so long as they are not anywhere too warm (in which case the icing will soften).