※ I changed the recipe to add the option of substituting katakuriko or joshinko for the cornstarch.

Put the cake flour, white sugar, cornstarch, and salt in a bowl and mix well with a whisk.

Pour the olive oil into the bowl in a swirling motion as if you are drawing circles.

Using a rubber spatula, mix with a cutting motion until the oil and flour have combined and the mixture looks crumbly. If the dough won't come together when you squeeze it with your hands, add a little more olive oil.

Put the crumbly dough into a plastic bag.

Squeeze the bag briefly with your hands to bring the dough together.

Let the dough rest in the refrigerator for 30 minutes (you can skip this step if you don't have time).

Take the dough out and let it sit at room temperature for about 10 minutes (cold dough is hard to work with). Form into a 3cm cylinder and flatten the sides. Preheat the oven to 320F/160C.

I use a milk carton to make a sort of "sushi mat" in order to form the dough. Press and squeeze firmly to shape the dough.

Use a knife to cut the dough into 1cm pieces. I made square cookies, but you can make any shape you like.

Bake in an oven preheated to 320°F/160°C for 10 minutes. Then turn the oven down to 302°F/150°C and bake for 5 more minutes. Be careful not to let the cookies brown.

When little cracks appear on the surface of the cookies, they're done. They crumble easily, so let them cool before handling them.

This is the olive oil I generally use. You can clearly taste the olive oil flavor in these shortbread cookies, so I recommend using a good quality olive oil.

I use scissors to cut out a piece of milk carton and then fold it to use in shaping the dough. It's really easy and convenient and the cookies turn out beautifully.