First, make the pastry cream. Click on the “pastry cream” link in the ingredients list and follow the instructions.
In a bowl whip together whipping cream and sugar to get soft peaks. Place the cooled pastry cream to a bowl of a stand mixer fitted with a whisk attachment or place in a large bowl. Beat for about a minute. Gently fold in (in thirds) the whipped cream. Don’t overwork it. The cream must be nice and light. Transfer vanilla cream to a piping bag, fitted with a round pastry tip, and keep chilled in a refrigerator until ready to pipe onto choux puffs.
In a clean bowl of a stand mixer or using an electric mixer beat the butter, packed light brown sugar, and icing sugar. Add the all-purpose flour and mix until the flour is completely incorporated. Flatten the dough and transfer to a sheet of parchment paper. Cover the dough with another sheet of parchment paper and roll to 2 mm / 5/64 ″ thickness using a rolling pin. Transfer to large baking sheet and freeze until needed.
Make the choux pastry. Click on the “choux pastry” link in the ingredients list and follow the instructions until the baking step.
Transfer choux pastry dough to a pastry bag fitted with a star pastry (1 cm / 1/2 inch) tip. Line two large baking sheets with parchment paper. Pipe out 12 choux mounds, about 5 cm / 2-inches round, onto the prepared baking sheets. Evenly space them apart to prevent touching during baking. Using a water-moistened finger, smooth down the peaks. Preheat the oven to 190°C / 375°F.
Craquelin and Choux Pastry
Remove the Craquelin from the freezer and cut 16 circles (5 cm / 2-inches) round from the dough. Place each Craquelin circle on top of the choux mound.
Place the baking sheet (bake in two rounds) in the oven. Bake for 20 minutes at 190°C / 375°F in a regular oven or for 20 minutes at 180°C / 355°F in a convection oven. Then, open the oven door to release the steam, close the door and bake for another 15 - 20 minutes at 170°C / 340°F in a regular oven, or for about 15 - 20 minutes at 160°C / 320°F in a convection oven. Baked choux buns will be golden brown and beautiful outside and nice, baked inside. Remove from oven and set on cooling rack to cool.
Mascarpone Whipped Cream
In a bowl mix together whipping cream, sugar and vanilla seeds until you get nice, soft peaks, using an electric mixer. In a separate clean bowl beat the mascarpone using an electric mixer. Gradually (in thirds) fold in the whipped cream to get a nice, glossy mixture. Transfer mascarpone whipped cream to a piping bag, fitted with a star pastry tip, and keep chilled in a refrigerator until ready to pipe onto choux puffs.
Assemble and Serve
Assemble: Using a serrated knife, cut 1/3 of the top off each choux bun. Set the cut tops aside. Pipe the vanilla cream into the shell until 3/4 full. Repeat the filling process with each choux puff. Pipe two swirls of the mascarpone whipped cream on top, reserving a bit of cream to decorate the tops later. Place the cut top on top of the mascarpone whipped cream and decorate each cream puff with a small swirl of mascarpone whipped cream, half candied sour cherry and chopped pistachios or however you desire. Choux puffs are best enjoyed the same day. Store in a fridge for up to a day.