Cream butter and sugar together. Add egg yolks, 1 at a time, and mix thoroughly. Add vanilla extract. Add flour and salt slowly and mix until dough comes together. Finish kneading dough on a work surface until smooth. Wrap in cling film and chill for at least an hour.

To shape and bake cookies: Preheat oven to 325 degrees F. Pull dough from refrigerator and let sit for 10 to 15 minutes to soften a little. Dust work surface with flour and roll out dough to about ¼-inch thick. Cut desired shapes and place them on a parchment-lined baking sheet. Bake cookies for about 12 to 15 minutes. Let cool before decorating.