1In a medium bowl, combine salt, water, and vinegar, stir until the vinegar dissolves.
2In another bowl put the flour, make a well in the center, add the liquid and butter cut into small pieces.
3Quickly mix the ingredients with your fingers until crumbly.
4Form a ball with the dough.
5Set aside for at least 1 hour in the refrigerator.
6Place the ball on a floured surface, roll out using a rolling pin to form a rectangle 50 X 20 cm.
7Fold the dough in thirds, like a business letter. This completes the first turn.
8Rotate the dough 90 degrees so that the folded edge is on your left and the dough faces you like a book. Roll out the dough again. Once again, the dough should be in a smooth, even rectangle.
9Fold the dough in thirds again, completing the second turn.
10Repeat the rolling and folding technique until the dough has had a total of three turns.
11Put it in the refrigerator wrapped in plastic.
12Chill for at least 30 minutes before using.
13Remove the dough from the refrigerator and on a floured working surface let it warm up for 5 minutes and roll it out again in a 50 X 20 cm rectangle, fold in thirds again, completing a fourth turn.
14Repeat the rolling and folding technique until the dough has had a total of eight turns.
15In a bowl, mix the egg yolks and the sugar. Add the cornstarch.
16Boil the milk and the split vanilla bean in half, lengthwise. Let it steep for 15 minutes.
17Pour the milk into the egg mixture, mix well and return to the saucepan.
18Cook over low heat and allow to boil, stirring regularly until it thickens.
19Put the cream into a bowl to cool down.
20In another bowl beat the butter and confectioner's sugar, add eggs, flour, ground nuts, and clementine zest. Mix until smooth.
21Add 200 gr. of chilled pastry cream and stir.
22Roll out the dough on a floured surface to form a rectangle 40X30 cm.
23Place it on a floured baking sheet and let it stand for 30 minutes in the refrigerator.
24Cut 2 discs of 20 cm diameter.
25Place one disc on a baking sheet, prick with a fork.
26Spread the pastry cream in the center, leaving 1 cm around the edge. Place the king figurine or prize.
27Moisten the edge of the disc with a brush and a little water.
28Place the second disc on top and seal the edges with your fingertips or using a fork.
29Make cuts with a knife around the cake and also on top to decorate.
30Glaze with egg yolk beaten with milk and with a knife draw shapes on top.
31Preheat the oven to 175 degrees Celsius and bake for 40 minutes.