Preheat the oven to 350 degrees F
Gently mix (I love my KitchenAid to mix things) the butter, egg, sugar and vanilla together
In a separate bowl mix the flour, baking soda and salt
Gradually all the dry mix to the wet, in 3 batches, adding a tsp of milk after each batch
When the cookie batter is mixed well, make 1 inch balls
Place each ball on a cookie tray/pan, gently pressing down on each ball to flatten very lightly
Bake on the middle rack of the oven for approximately 10 minutes.
Remove and cool before frosting each cookie.