Preheat the oven to 350 degrees F.
Cream the butter and sugar in the bowl of an electric mixer fitted with a paddle, on medium speed, scraping down the sides of the bowl as necessary.
Cream the mixture until it is smooth and fluffy.
Add the egg yolks 1 at a time, mixing in between each addition. Scrape down the sides of the bowl. Beat for 1 minute and add the vanilla.
Combine the flour and the salt in a medium-size mixing bowl. Mix well. Add the flour mixture to the butter mixture and mix on low speed until it is fully incorporated. Increase the speed to medium and mix until the batter is thick and creamy, about 2 minutes. Scrape down the sides of the bowl and the paddle.
Lightly flour a flat surface. Using a rolling pin, roll out the dough to 1/4-inch thick. Cut the dough into the desired shapes.
Line a baking sheet with parchment or waxed paper. Place the cookies on the baking sheet about 2 inches apart.
Bake until lightly golden, about 20 minutes. Remove the cookies from the oven and let cool completely in the pan. Remove the cookies from the pan using a spatula.
Repeat the process until all the dough is used. Frost each cookie and garnish with sprinkles.