How to cook
I used a tray measuring 12 1/2″ (32 cm) x 8″ (20 cm) x 2 3/4″ (7 cm). For a better result, use one that's 10″ (25 cm) long. Make the cream by putting 4 1/5 cups (1 L) of the milk with the sugar in a pot. Put it on the stove and heat to boiling point.
Pour the rest of the milk in a bowl and dissolve the puddings and starch in it. Stir until you get a homogeneous porridge-like mixture. Once the milk starts boiling, slowly pour the mixture into it in a thin trickle and stir nonstop to obtain a thick, smooth cream.
Remove from the stove, cut the butter into pieces and add it to the hot cream, along with the vanilla. Stir until the butter melts. Cover the cream with foil and leave to cool.
Prepare the layers by first rolling out the puff pastry lightly. Cut it into 2 equal parts - you can lay the tray down and cut along its outlines. If using a smaller tray, decrease the puff pastry to 14 oz (400 g).
Put baking paper onto a cooking grid. Take a fork and poke several holes in 1/2 the puff pastry so it doesn't puff up too much during baking (mine still puffed up even with holes).
Transfer it onto the cooking grid. Cut the other 1/2 of puff pastry lengthwise down the middle, then cut into approximately identical pieces. Poke a few holes in each piece with the fork and put them on the baking paper on the cooking grid next to the whole piece of puff pastry.
Heat the oven to 392°F (200 °C) and bake the puff pastry about 12 min. until golden. Take them out and leave to cool.
Put the whole piece of puff pastry in the tray, pour all of the cream on top and even it out.
On the very top, arrange the cut pieces of puff pastry, pressing them lightly into the cream. Leave the cream pita to cool and put in the fridge for at least 6 hours to harden. Sprinkle with powdered sugar at the end and cut into slices.
The recipe was adapted from culinary blog Ossigeno.