Prepare the custard first; it needs to cool before being used in the cake. Pour the milk into a medium-sized saucepan and whisk in the 1 tablespoon flour. Heat the milk over medium heat until steaming hot, not boiling. Meanwhile, in a mixing bowl combine the sugar, egg yolks and raspberry extract. Whisk until the mixture is light and pale and ribbons off of your whisk. Prepare the cornstarch slurry. Combine the cornstarch and milk and stir until smooth. Pour the slurry into the egg and sugar mixture and whisk until well combined.

Once milk is hot, slowly add it to the egg yolk mixture; pour in a little bit at a time and whisk vigorously after each addition until all of the milk is added. Pour the custard back into the sauce pan and cook over medium heat, stirring non-stop, for about 3 to 4 minutes. The mixture should thicken into pudding-like consistency. If any clumps form, whisk until the custard is smooth. Transfer the custard into a small bowl, covered with plastic wrap and set into the refrigerator to cool completely. The custard can also be prepared the day before.

Prepare the puff pastry layers next. Preheat oven to 375F. Thaw the puff pastry sheets overnight in the refrigerator or at room temperature, until soft. Unfold the sheets on parchment paper. Using an 8 or 9-inch round plate or pan, cut out a circle from each pastry sheet. Pierce each layer with a fork to keep the layer flat while baking. Transfer the layers on baking sheets lined with parchment paper, brush the tops with the beaten egg, and sprinkle with sugar for a caramelized finish. Bake the puff pastry until golden brown on top. Allow the pastry to cool on the pan until cool enough to touch, then transfer onto a wire rack to cool completely.

Prepare the whipped cream filling. Place the softened butter and cream cheese into a mixing bowl and whisk on high speed until light and fluffy. Add the cold heavy cream and sweetened condensed milk. Mix on medium speed until a smooth and fluffy frosting forms. Take care to not overmix the filling as overmixing will cause it to separate. Transfer the cream into a pastry bag; I used tip #4FT.

Assemble the cake. Spread a generous amount of the custard onto each pastry sheet, then pipe dollops of whipped cream along the edges of the layer and into the center. Add fresh berries around the rim as garnish and into the center. Repeat for each layer, including the top.

Garnish the top with more whipped cream frosting. If desired, drizzle the top with melted dark chocolate. Melt chocolate in the microwave, then transfer into a ziplock bag, cut off the tip and drizzle over the cake.

Once the cake is assembled, it needs to be refrigerated for at least 6 hours, or best overnight, to allow the layers to set.