Clementine Napoleons

Preheat oven to 375°F (190°C).
Roll out puff pastry on a lightly floured surface and cut into 16 rectangles 1¾ in. x 3 in. (4 cm x 8 cm).
Transfer to a baking sheet and bake until golden brown. Cool.
Custard
In a bowl, beat egg yolks and cornstarch together. Set aside.
Combine milk, cream and sugar in a pot and bring to a boil over medium heat. Whisk and remove from heat.
Whisk 1 cup (250 mL) of the milk-cream mixture into the egg yolks.
Return to the pot and continue cooking until mixture bubbles. Remove from heat.
Stir in Grand Marnier and zest. Cover custard, laying plastic wrap directly on it, to prevent a skin from forming, and cool.
Assembling Napoleons
When custard has cooled, assemble Napoleons
Spread 8 puff pastry rectangles with 3 Tbsp. (45 mL) each of custard.
Add a few clementine supremes and top with another rectangle.
Place 8 Napoleons side by side to ice them.
Using a fork, dribble lines of icing in lines on Napoleons.
Gently lay a few supremes on top.
Decorate each Napoleon with a piped whipped cream rosette.
Serve with clementine coulis. 
Icing Clementine coulis 
Cream butter and add salt. 
Add icing sugar and juice, alternately. Add vanilla.
Beat until smooth.
Clentine coulis
Purée in a blender