Blueberry Dome Cake

Preheat the oven to 150 °C fan (convection) and line two baking sheets with parchment paper.

Separate the eggs. Beat the egg whites with 5 tbsp hot water until stiff, then gradually add 180 g sugar and continue beating until dissolved.

Briefly fold in the egg yolks.

Mix the flour with baking powder and gently fold it into the egg mixture until no streaks of flour remain.

Spread the batter evenly across both baking sheets.

Bake both sponge sheets in the oven for about 15 minutes.

Heat the blueberry jam with 3 tbsp water and smooth it out.

Sprinkle a clean tea towel with sugar. Turn a hot sponge sheet onto it, peel off the parchment, spread a thin layer of the warm jam and, using the towel, roll it up very tightly. Let cool on a rack.

Repeat with the second sponge sheet, rolling it into a roulade as well and let cool.

Soak the gelatin sheets in cold water. Wash the blueberries and pat them dry.

Stir mascarpone, low-fat quark, lemon juice, vanilla sugar and 150 g sugar until creamy.

Squeeze out the gelatin, dissolve it gently and stir into the cream. Whip the cream until stiff and, as soon as the cream starts to set, fold in the whipped cream and the blueberries.

Slice the roulades into rounds about 1 cm thick. Line a round glass bowl (about 1.5 l) with cling film and completely line it with the sponge slices.

Pour the cream into the mold, smooth the top and finish with the remaining sponge slices.

Chill the dome cake for 3–4 hours (or overnight).

Carefully invert the dome cake onto a plate and peel off the cling film.