Add salt, baking powder and flour and mix until well incorporated.
Cover dough bowl with plastic wrap and chill in the refrigerator for one hour.
Preheat oven to 350°F.
Line a baking sheet with parchment paper or a silicone baking mat.
Roll cookies into 1-inch balls and flatten with the bottom of a drinking glass until ¼-inch thick.
Bake for 8-10 minutes, or until slightly golden brown on the bottom.
Let cool completely.
In a stand mixer or large mixing bowl, beat together powdered sugar and butter until creamy. Mix in vanilla and milk until smooth.
Frost cooled cookies with frosting and top with sprinkles, if desired.
Notes
Use food coloring to add to the frosting if you want to! Then frost the cooled sugar cookies with frosting and top with sprinkles of your choice if you desire it.
If the frosting is not thick enough, add a little more powdered sugar. If it's too thick add in a little more milk.
For an extra creamy frosting, add in a few tablespoons of shortening. (It's so delicious!)