Cardinal slices

Method

1. Prepare the cream. Dissolve the espresso powder in the hot water and let it cool completely. Wash the orange with hot water and finely grate only the orange part of the peel. Stir together the coffee, zest, and cold heavy cream. Cover and refrigerate for at least four hours so the zest can infuse the coffee cream.
2. Prepare the baking sheet. Preheat the oven to 180 °C using top and bottom heat, with the fan off. Cut two strips of parchment paper, each about 13 × 42 cm, and place them side by side on a baking sheet. Have two piping bags with plain round tips ready.
3. Whip the meringue. Begin beating the egg whites with the salt. Gradually add the sugar and keep beating until the mixture is stiff and glossy. Transfer to the first piping bag.
4. Make the sponge batter. Beat the egg yolks, whole egg, and sugar for about five to eight minutes until pale and thick. Mix the flour and almonds and gently fold them in. Transfer immediately to the second piping bag.
5. Pipe the strips. Pipe three long strips of meringue onto each strip of paper, leaving about two centimeters between them. Fill the two gaps with sponge batter. Dust lightly with powdered sugar and bake immediately.
6. Bake. Use a wooden cooking spoon to hold the oven door slightly ajar, provided the oven continues to heat with the door open. Check for the first time after 18 minutes. Bake for about four to seven more minutes, until the surface is dry and only lightly colored. If the oven switches off when the door is open, keep the door closed and briefly let moisture escape when checking.
7. Let cool. Slide the two strips, still on their parchment paper, off the hot baking sheet onto a wire rack. Let cool completely, then carefully peel off the paper. Small broken pieces can be used as part of the bottom layer when assembling.
8. Fill and slice. Begin whipping the cold coffee-orange cream. Mix the powdered sugar and whipped cream stabilizer, add them gradually, and whip the cream until stiff. Place one pastry strip on a platter, spread the cream over it, and carefully place the second strip on top. Chill for at least 30 minutes. Dust with powdered sugar and use a sharp knife to cut into eight slices. Keep chilled until serving.

From the world of the novel: The Kupferstern and its secret recipe card are fictional. This version was put together for the website from publicly available baking recipes; the orange zest infused in the cold coffee cream follows the novel.