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For the fondant icing
In a saucepan, heat the fondant to 95°F (36°C). Add the cocoa
butter, glucose powder, and cocoa powder. Thin with a little water if
necessary.
For assembly and finishing
Using a ⅜-inch (8-mm) tip, pipe 6-inch (15-cm)-long lines of the
choux paste. Repeat with a ¼-inch (7-mm) tip for 4-inch (10-cm)-
long lines and a ¼-inch (7-mm) tip for 1½-inch (4-cm)-long lines.
Preheat the oven to 360°F (180°C). Place the lines of choux paste
on a baking sheet lined with parchment paper and bake in the oven
for 30 minutes. Remove from the oven and set aside on a rack.
Fill each piece of choux pastry from below with chocolate pastry
cream, then with cocoa nib praline.
Pour the fondant icing, while still warm, into a pastry bag and, using
a basketweave tip, pipe a strip of it over each filled piece of choux
pastry. Superimpose the choux pastry pieces from the largest to the
smallest.