How to make
Prepare the dough by sifting the flour into a bowl and add the baking powder, sugar and ground almonds or hazelnuts. For my cake in this case I used hazelnuts, but according to the original recipe it is made only with almonds. It is best that they are peeled, but even if they are not, it is not a problem.
Add the yolk, vanilla sugar and soft, half-melted butter. Knead the dough, form it into a ball and put it in the fridge for at least an hour.
During this time, prepare the cream by putting most of the milk with the cream and sugar over moderate heat. Cut the vanilla pod in half lengthwise and drop the seeds inside.
Beat the yolk with the remaining milk, vanilla sugar, ground almonds and flour. Pour this mixture in a thin stream over the milk, which has not yet boiled, but has simmered on the hob. Stir vigorously, until the cream thickens. Add the rum and butter and cook for another two or three minutes on low heat, then remove it from the heat and stir periodically, so that it doesn't aquire a crust.
Divide the hardened dough into two parts - one smaller than the other. Prepare a round pan with a diameter of 8.5″ (22 cm), covered with baking paper or greased and floured. With most of the dough we need to cover the bottom and at least 0.4″ (1 cm) and a half of its walls.
Since rolling out a crumbly dough is difficult, you can do it directly with your hands in the baking pan, by pressing and leveling it out. The base should be about 0.1″ (0.3 cm) thick. Pierce it lightly with a fork and pour the cream over it.
The second, smaller part of the dough should be rolled out, so that our cake is even and beautiful on top. To do this, lay cling film, roll out the dough into a round shape with the diameter of the baking pan and then lift and turn it over the cream. Join the ends of the two crusts, by sticking them together.
Coat the surface with lightly beaten egg whites and sprinkle with brown sugar and sliced almonds.
Bake the cake in a preheated oven at 360°F (180 degrees) for 35 minutes or until it aquires the desired color.
Leave it to cool and refrigerate it for at least two hours before cutting and serving it.
Tip: Use a cake pan with a detachable bottom, so that you do not have to transfer the cake into another tray, as there is a risk of it falling apart. It is delicate, because of the crumbly dough, but it is worth the effort because its texture and aroma are wonderful!
Enjoy! The Traditional Pais Vasco Cake is ready.