Make the caramelized walnuts from "Cinnamon-Scented Caramelized Walnuts". If you dislike cinnamon, please omit it.

As we are including walnuts in the cookies this time, go ahead and break the walnuts into smaller pieces. Please follow the amount listed in the ingredients.

The walnuts used in the cookie dough should be ground into powder using a food processor or pestle & mortar. Instead of "almond powder" we are using "walnut powder".

Walnut powder will turn out like this. Because we are using raw walnuts, it will turn a bit paste-like when using a food processor, but it smells great!

If Step 3 is too much effort, then you may substitute 40 g of store-bought almond powder and go straight to Step 10.

Combine the cake flour and the walnut powder and sift 2-3 times. The particles from the walnut powder are large so it's better to sift at least twice.

Because the walnut powder will be somewhat paste-like in consistency with large particles, it is easier to use a rubber spatula and push the walnut powder through the sifter with the cake flour.

After sifting 3 times, the walnut powder will turn into a beautiful fine powder together with the flour as in the photo.

If you are using almond powder, combine it with the cake flour and sift once. Sift the powdered sugar separately for both almond and walnut powder.

Separate 1 egg yolk from the whites. The egg whites can be stored in the freezer.

Whip the butter, which was left at room temperature or microwaved, until creamy in texture.

Add the sifted powdered sugar to the butter and whip until creamy.

Add the egg yolk into the butter and whip some more.

Add the walnut or almond powder in 2 batches to the butter mixture, and then add the essence. Switch to a rubber spatula and mix as though you are cutting the dough each time.

Once the dough looks like this you may stop. The texture will be slightly crumbly. Remove the dough on the rubber spatula as you mix.

Add the caramelized walnuts from Step 1 into the mixture and an essence of your choice. Mix thoroughly with a rubber spatula as though you are cutting through the dough.

Knead the dough together firmly into an oblong shape and place it on top of some plastic wrap. (I put the dough together quickly by hand in order to avoid over-kneading.)

Roll into a stick about 3 cm in diameter and wrap tightly with plastic.If not wrapped tightly here, it will be difficult to cut out the cookies later.

Place in a freezer for 2 hoursto solidify. Remove from the freezer and cut the cookies a little less than 1 cm thick. Place them on a baking sheet.

Bake in an oven pre-heated to 180°C for 15-20 minutes. The time will vary according to your oven.

If you over-bake, the texture will not come out well. Freshly baked cookies are BEST when you softly press the top and they are slightly soft to the touch. They will harden momentarily.

The combination of the ingredients will result in a very crispy and crumbly texture. Freshly baked cookies are very fragile, so please take care!

I have ended up with this combination of ingredients after experimenting with tart dough. The dough is very crispy and crumbly to the point that, as a tart, it would break apart and not work.

The caramel that oozes from the dough is delicious. It's the ultimate for someone like me who loves walnuts.

The cookies will maintain the crispy crumbly texture for days when stored in an air-tight container. If you include silica gel, they'll keep even longer! They're great as a present!