Preparation: Cut the butter into about 2 cm-thick slices, and bring them to room temperature. Sift the cake and almond flour together.
Add caster sugar into the butter. Mix as though grinding until white and fluffy. It's easy if you use a handheld mixer.
Add the egg yolk, salt and vanilla oil, and continue to mix.
Sift the mixed flour into the mixture. Cut and fold it in until it's not powdery.
The cookie dough is done!
Wrap tightly with plastic film. Rest in the refrigerator for about an hour.
Knead the cooled and hardened dough on the work surface dusted with flour (bread flour). Be careful not to make the dough too soft! If the dough gets too soft, cool in the refrigerator again.
Divide the dough in half, and form into a log of your favorite size. I roll each portion into a roughly 2cm-wide log. Shape them smaller than you think, because the dough swells during baking!
Wrap with plastic wrap, and rest in the refrigerator again for more than an hour. You can freeze the dough at this step.
Take out from the refrigerator, and roll the dough again to soften the surface a bit.
Roll the dough in a lot of sugar in a tray. Coat the dough's surface with generous amount of the sugar.
Cut into 8mm - 1cm thick slices. Bake in the oven for 15 minutes at 340F/170C.
Story Behind this Recipe
This is the basic cookie I always bake. You can freeze the dough, so I often make a lot of dough when I have time,and keep them in the freezer! If you put vanilla beans instead of the oil, the cookie will be richer and more delicious.
The trick is to mix the butter and sugar well! Make the mixture airy and fluffy. When you knead the chilled dough, don't hesitate and knead thoroughly! If the dough warms up, gluten develops and makes the cookie less crispy, so be careful in summer .