1. First we prepare the Yudane the night before : Add bread flour and salt in a heatproof bowl. Add boiling water and mix well, using spatula until until uniformly blended. Cover with plastic wrap and put it in the fridge overnight or (if you forgot) at least for 5 to 6 hours.
2. Add all bread ingredients and the yudane (torn into small pieces) from #1 in the pan of your bread machine (as per manufacturer instructions). Select dough cycle and press start.
3. When the dough cycle is complete, remove it from the machine and place on the floured surface. Punch the dough down and cover it with a wet cloth. Take bench time for about 15 to 20 mins.
4. Gently pat the dough down and roll it into about 30cm diameter circle onto the baking sheet. Let it rest in a warm place for 45 to 60 mins - This is the second fermentation.
5. Heat oven to 170C degree.
6. Brush the bread with egg lightly and sprinkle some nib sugar. Set the temperature to 150C degree and bake for about 20 mins or until golden. Remove from the heat and let cool down on a wire rack. Set aside.
Butter cream filling
7. Beat meringue powder (8g) and water (56g) in a large bowl with an electric mixer until soft peaks, then add sugar (25g). Continue mixing until stiff.
8. Combine sugar (80g) and water (35g) in small saucepan, bring to a boil until the temperature reach 115℃ degree. Immediately while beating, pour the hot sugar syrup over beaten meringue slowly, beat until whites are stiff and glossy.
9. In a another bowl, add butter / for the cream A (or mascarpone cheese and butter / for the cream B) and beat until soft. Gradually add the Italian meringue from #8 into the butter until smooth.
Add vanilla syrup (1 tbsp / optional) or strawberry puree (4 tbsp / optional) if you want.
10. Cut the cake horizontally in half. Spread the filling cream over the bottom half and cover with the top of the cake.