Cut an 8-inch (20cm) round from the baked puff pastry.
Place the puff pastry disk on a serving platter.
Place a cake ring around it and line it with acetate sheets.
Spread one-third of the vanilla custard filling evenly over the puff pastry.
Spoon half of the raspberry sauce over the surface. Use a skewer or toothpick to create gentle swirls.
Carefully spread another third of the vanilla custard filling on top.
Continue adding the remaining raspberry sauce and swirl again.
Finish with the last third of the vanilla custard filling.
Smooth the top with an offset spatula.
Break the remaining puff pastry into crumbs. Spread them evenly on top of the vanilla custard filling.
Refrigerate for at least 4-6 hours or overnight.
Before serving, dust the cake with powdered sugar. Slice with a hot knife and enjoy!