• Make the filling: Place the poppy seeds in the bowl of a high-speed blender and blend on medium speed until very finely ground, about 30 seconds. Transfer to a medium saucepan with the milk, orange juice, prunes, honey, and granulated sugar. Bring to a boil over medium-high heat, stirring until the sugar dissolves, then reduce the heat to medium and cook, stirring (more frequently toward the end), until most of the liquid has been absorbed and the mixture has thickened to a pudding-­like consistency, 3-5 minutes. Remove from the heat and let cool for 5 minutes. Return the poppy mixture to the bowl of the blender. Add the vanilla, lemon zest, orange zest, salt, cinnamon, and ¼ cup water. With the lid slightly vented, blend on medium speed for about 2 minutes, until smooth with only a bit of  texture from the poppy seeds remaining. Pause occasionally to scrape down the sides, and, if necessary, add more water to help it blend, 1 tablespoon at a time. Add the egg whites, blend again until fully incorporated, and set aside.

• Make the topping: In a medium bowl, whisk together the flour, brown sugar, cinnamon, and salt. Add the butter and, using your fingers, work it in until the mixture is evenly moistened and clumps together in pea-­size pieces. Cover and refrigerate.

• Make the batter: Preheat the oven to 176°C (350°F). Spread the walnuts in an even layer on a rimmed baking sheet and bake until toasted and fragrant, 8-10 minutes. Let cool, then coarsely chop. Brush a 9-by-13-inch baking pan with butter, then line with parchment paper, leaving an overhang on the two long sides. Brush the parchment paper with more butter; set aside. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, sugar, and salt on medium-­high speed until light and fluffy, 2-3 minutes. Add the egg and vanilla and mix to combine. With the mixer on low speed, add the flour and toasted walnuts and mix just until combined, with no visible spots of flour.

• Spread the batter into the prepared baking dish, smoothing it all the way to the edges with a small offset spatula. Dollop the plum preserves over the batter and spread into an even layer. Pour the poppy filling over the top and spread to cover. Break the topping into bite-size pieces and scatter over the top of the filling. Bake until the top is golden brown and the filling is set (a toothpick inserted into the centre should come out with little to

  no crumbs attached), 45-50 minutes.

• Let cool completely, then lift from the pan using the parchment paper overhang. Dust the

  top with confectioners’ sugar, then slice into squares. Once cooled and sliced, the bars keep well in an airtight container for 2 days at room temperature or up to 5 days in the

  fridge. They also freeze beautifully: Layer the bars with parchment paper and freeze for up to 3 months. Thaw overnight in the fridge, then bring to room temperature before serving.

• Note: Whole, fresh poppy seeds are essential. The pre-­ ground kind can be very bitter and compromise the flavour of the whole tray – don’t use them!

Recipe extracted from A Year of Jewish Joy: Inspired Recipes, Rituals, and Traditions for Beautiful Celebrations by Rebekah Lowin, published by Harper Collins

Instagram: @rebekahlowin