Boil the walnuts in boiling water for 5 minutes.
Remove the moisture from the walnuts, then bake them in the oven at 150°C for about 10 minutes.
Sift cake flour, add cold butter, and mix well using a scraper. Place the mixture in the freezer for 20 minutes.
Add 1 egg yolk, salt, and milk, then knead into a single dough ball.
In a silver bowl, add sugar, cinnamon powder, starch syrup, butter, and water and stir over a double boiler until the butter is melted.
Finally, add 2 eggs and whisk well until fully combined.
Roll out the dough from the refrigerator, lay it into a mold, prick holes with a fork, fill with roasted walnuts and filling evenly.
Bake in the oven at 180°C for 40 minutes.