Apple Sponge Cake with Plum and Cream Filling

For the dough, place half an unpeeled apple unpeeled aside. Peel remaining apples, cut flesh into 1 cm (approximately 1/2-inch) thick slices, then dice and mix immediately with 2 tablespoons of lemon juice. Preheat oven at 175°C (approximately 325°F).

Mix egg whites and 1 pinch of salt until stiff. Sprinkle in 75 grams (approximately 5 tablespoons) of sugar and continue to beat until sugar has dissolved. Stir in yolk. Sift in flour and baking powder and carefully fold, then add apple cubes. Line bottom of a springform pan (26 cm)(approximately 10 inches) with parchment paper and spread dough on it. Bake on second shelf from bottom for 25–30 minutes. Remove from oven and let cool on wire rack.

For the filling, wash, pit and finely slice 500 grams (approximately 1 pound) of plums. Cut spongecake once horizontally, set springform pan rim around bottom layer and cover with plum slices. Prepare glaze with 25 grams (approximately 1 ounc) of sugar and cherry juice according to package directions and pour over plums. Chill for 30 minutes.

Soak gelatin sheets in a bowl of cold water until softened, about 10 minutes. Mix yogurt, orange juice and orange zest with 50 grams (approximately 1/4 cup) sugar. Squeeze out gelatine, dissolve in heated cointreau and stir into yogurt. Remove from heat as soon as it begins to gel and stir in 200 ml (approximately 1 cup) of whipped cream. Spread cream mixture over plums, replace upper tier of cake and chill for 3 hours.