Step 1: Prepare the Dough
In a food processor, pulse together flour, sugar, and salt.
Add cold butter cubes, pulse until coarse crumbs form.
Add egg yolks and lemon zest, pulse to combine.
Gradually add cold water until dough starts to come together.
Shape into a disk, wrap in plastic, refrigerate 30 minutes.
Step 2: Make the Chestnut Filling
If using fresh chestnuts, roast at 425°F for 20 mins, then peel.
Pulse peeled chestnuts in food processor until finely chopped.
Mix with honey, amaretto, vanilla, cinnamon, and salt in a bowl.
Step 3: Assemble the Cookies
Preheat oven to 350°F. Line baking sheets with parchment.
Roll out dough to 1/8 inch thickness on floured surface.
Cut into 2.5-inch squares.
Add 1 tsp filling to each square and fold diagonally into triangles.
Press edges to seal and brush tops with egg white.
Step 4: Bake
Place cookies 1 inch apart on baking sheets.
Bake 15-18 mins until edges begin to turn golden.
Cool on wire rack and dust with powdered sugar.