Preheat oven to 350 degrees and prepare baking sheets with parchment paper or Slipmats.
In a medium bowl combine the flour, baking powder and salt, and whisk together to blend.
In the bowl of an electric mixer, combine the butter and sugar and beat together on medium-high speed until soft and fluffy, about 2-3 minutes. Beat in the eggs one at a time, mixing well after each addition and scraping down the bowl as needed. Blend in the vanilla. With the mixer on low speed, add in the dry ingredients mixing just until incorporated and evenly mixed. Cover and chill the dough for 1 hour.
Scoop cookie dough and roll into a small ball. Press lightly on it to flatten it slightly. Bake for 10-12 minutes. Do not overbake.
To frost the cookies, place the confectioners’ sugar in a medium bowl. Add the melted butter, vanilla, and milk to the bowl and whisk until smooth. Whisk in additional milk as necessary, 1 teaspoon at a time, until you reach your desired consistency. Add food coloring if using. I used a knife to layer the frosting on and then topped with a few sprinkles.