In a medium bowl, sift together the flour, baking powder and salt.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth, about 2 minutes. Add the sugar and continue beating until the mixture is light and fluffy, about 3 minutes. Add the eggs one at a time, beating between each addition, then add the vanilla.
Turn the mixer off. Add the flour and then beat just until combined.
Divide the dough in half then shape each piece of dough into a log. Wrap each dough log securely in plastic wrap and refrigerate them for a minimum of 1 hour and up to a week. (See Kelly’s Notes.)
Remove the dough from the fridge, then roll each log in sprinkles (optional).
Preheat the oven to 350ºF and line two baking sheets with parchment paper.
Working with one log at a time, slice it into 1/4-inch rounds. Arrange the cookies on the prepared baking sheets, spacing them 1 inch apart. Freeze the cookies for 10 minutes.
Bake the cookies for 12 to 15 minutes until set. (See Kelly’s Notes.) Remove the cookies from the oven and let them cool for 5 minutes on the baking sheet before transferring them to a wire rack to cool completely. Repeat the slicing and baking process with the second log of dough.