Preparing the dough:
On a work surface mix flour and cornstarch. Shape in a mound with a hole in the center. Add in the well sugar, diced butter, two egg yolks, vanilla, grated lemon rind, and pinch of salt.
Mix the ingredients with the help of a fork, then combine the flour and knead to form smooth dough.
Cover with a plastic wrap and place in the refrigerator for one hour.
Preparing the custard:
Warm the milk with the lemon peel. In a small saucepan place egg yolks, sugar and beat vigorously, until they become pale yellow and creamy. Incorporate the flour a little at the time.
Add the warm milk, heavy cream, and vanilla stirring continuously.
Place on low heat and stir constantly with a wooden spoon.
Remove from the stove when the cream starts boiling and becoming denser.
Remove lemon peel, transfer the custard in a bowl and cool at room temperature.
Assembling the cake:
Preheat oven 375 F (190 C). Butter the pan, and sprinkle with a small amount of flour.
Remove the dough from the refrigerator. Reduce the dough to ¼” (1/2 cm) thick disk with the help of a rolling pin. Cover bottom and sides of the pan with the dough.
Fill with the custard, and level with a spatula. Spread the pine nuts on the surface of the custard.
Bake for about 50 minutes. Let cool at room temperature, un-mould and serve cold, sprinkled with powdered sugar.