In a medium bowl, whisk together the flour, salt and baking powder. Then set aside.
2 ½ cups (313 g) all-purpose flour, spooned and leveled, ½ teaspoon baking powder, ½ teaspoon salt
In a large bowl, cream the butter and granulated white sugar together with and electric mixer on high speed until it's fluffy, 2-3 minutes. (You can also use a stand mixer fitted with a paddle attachment.)
1 cup (224 g) unsalted butter, softened, 1 cup (200 g) granulated white sugar
Add in the egg yolk and vanilla and mix on medium-high speed until pale in color and fluffy, 1-2 minutes.
1 egg yolk, 1 teaspoon vanilla
Add the dry ingredients to the wet ingredients and mix on low then medium speed just until combined. (Scrape the sides of the bowl as necessary.)
Scoop the dough with a small cookie scoop into 1 tablespoon portions. Then, roll them into balls. After each ball is rolled, immediately press it with a ¼ teaspoon to make an indent.
Chill the prepared cookie dough on a parchment paper lined baking sheet for 1 hour. (Chill the dough all together on one baking sheet, then separate out to bake.)
15 minutes before you're ready to bake the cookies, preheat the oven to 350 degrees.
Once chilled, separate the cookies 12 at a time on a large, parchment paper lined baking sheet and bake for 9-10 minutes.
When the cookies are straight out of the oven, scoot a small, round cookie cutter around them in a circular motion to help them return to their original smaller sizer. You can also press the centers again with a ½ teaspoon to create a deeper indent. Let the cookies cool for 5 minutes on the cookie sheet, then transfer them to a cooling rack to completely cool.