For the mochi: Carefully sift together 1/2 cup of the mochiko powder, the sugar and 3 tablespoons of the cocoa powder in a metal mixing bowl. Gently whisk in 1/2 cup water with the powder mixture in a ceramic bowl until the powder is completely dissolved. Steam the mixture in the microwave for 8 minutes, then mix. Microwave for 3 more minutes, then mix. Microwave for another 3 minutes and mix again. The mochi should shrink and pull away from the bowl into a round shape.
Using a towel, carefully remove the bowl from the steamer and set aside to cool, 2 to 3 minutes. On a wooden cutting board, spread the remaining 3 tablespoons of mochiko powder around the center of the cutting board. Using a spoon or spatula, scoop the mochi in the center of the board and spread more mochiko powder on top of the mochi. Using a rolling pin, roll the dough out evenly to 1/3-inch thick. Cut the dough into 1/3-inch square pieces with a knife, then dust off any excess mochiko powder from the cut mochi pieces. In another metal bowl, thoroughly mix together the mochi pieces and the remaining 1 tablespoon of the cocoa powder. Set aside the chocolate mochi to be used later in the serving preparation process.
For the cream: In the bowl of a standing mixer fitted with a dough hook, add the eggs and superfine sugar together. Mix on medium speed until thoroughly combined, 2 minutes. Add the mascarpone and mix on low speed until the cheese breaks into smaller chunks, 2 minutes. Then turn up the speed to high speed until well combined, 1 minute.
In a separate bowl using a hand mixer, whisk the manufacturing cream to soft peak. Combine the cream with the mascarpone mixture and mix on medium speed for 1 to 2 minutes. Add the crushed cookie pieces into the cream mixture and gently fold in with a spatula for 10 seconds.
Combine the espresso coffee with the amaretto. Cut the ladyfingers in half and dip them into the coffee mixture, making sure they are soaked through. Place a single layer of ladyfingers on the bottom of a serving cup. Add a layer of mascarpone cream mixture on top of the ladyfingers. Next, add a layer of chocolate mochi on top of the cream. Add another layer of ladyfingers on top of the mochi. Spread a final layer of cream to top off the cup. Repeat this process with the other 5 serving cups. Let the dessert cool in the refrigerator for at least 5 hours.
Before serving, decorate the dessert with a chocolate cream cookie and chocolate straw cookie.