1To prepare the yeast starter:
2Dissolve the yeast in the warm water, add the sugar, egg yolk, and flour.
3Knead until the mixture is smooth and uniform in consistency.
4Cover and let rise until it has doubled in size, approximately 50 to 60 minutes.
6To prepare the first kneading:
7Add the starter to the yeast dissolved in the water, sugar, flour, and egg.
8Knead vigorously, then add the butter, kneading until it is completely incorporated.
9Cover and let the dough rise until it has doubled in size, approximately 45 minutes in a warm area.
11To prepare the second kneading:
12Add the eggs, sugar, flour, salt, and the seeds of the vanilla bean to the dough, knead the dough until all the ingredients have been completely incorporated, approximately 8 to 10 minutes.
13Flatten the dough, fold it over, place it in a bowl greased with some butter, cover it and let it rest for approximately 1 hour, until it has doubled in size.
14Place the bowl in the refrigerator for 30 to 40 minutes.
15Place the dough on the work surface and roll it out with a rolling pin into a square, place the butter in the center.
16Bring the 4 corners of the dough to the center enclosing the butter, delicately roll out the dough to a rectangle and fold the rectangle into 3 parts.
17Refrigerate the dough for 15 to 20 minutes, roll it out again to a rectangle and fold it over into 3 parts, refrigerate for an additional 15 to 20 minutes.
18Repeat this step once more and refrigerate for another 15 to 20 minutes.
19At this point, shape the dough into a ball, kneading it on the work surface with buttered hands.
20Place the dough in a 3 liter, star-shaped buttered Pandoro cake pan, approximately 20 centimeters high.
21Cover the dough and let it rest until it reaches the top of the pan.
22Bake in a preheated oven at 170C for 15 minutes then lower the oven temperature to 160C for an additional 10 minutes.