Start your cookie-making process by preheating your oven to a temperature of 350 degrees Fahrenheit. This is an essential step as it helps make sure that the oven is at the right temperature for the cookies to bake evenly.

Once your oven is preheated, place your walnuts on a baking tray and toast them in the oven for about five minutes. Keep an eye on them to prevent burning.

Once the walnuts are toasted to a golden brown color, remove them from the oven and set them aside to cool.

While your walnuts are cooling, take a large bowl and sift all your dry ingredients into it. These include flour, salt, and baking powder. Sifting helps to aerate the ingredients and remove any lumps.

After sifting, mix these ingredients together until they're well combined and then set your bowl aside.

In the bowl of a stand mixer with a paddle attachment, beat together the butter and sugar on high speed. Continue until the mixture is creamed and has become a light pale color. This process incorporates air into the mixture and helps give your cookies their fluffy texture.

Reduce the mixing speed to low and carefully add the egg yolks, vanilla and orange extract, orange zest, and your cooled, finely chopped walnuts. These ingredients add flavor and richness to your cookies.

Now, it is time to incorporate your dry ingredients into the wet mixture. Add the flour mixture to the wet mixture half a cup at a time. This gradual addition prevents the formation of lumps and ensures a smooth dough.

Once your dough is ready, use a scoop that measures about one and a half inches to portion out your cookie dough. Roll each portion into a ball using your hands.

Place the cookie dough balls onto a non-greased baking sheet. Bake your cookies for approximately twenty minutes, or until the edges are a light golden color.

As soon as your cookies are baked and still hot, roll them in powdered sugar. This gives them a sweet, delicious coating. After this, place your cookies onto a cooling rack to cool. By the time they're cool, they'll be ready to enjoy!