Preheat oven to 350°F
Line baking sheets with parchment paper.
Cream the butter and sugars together in a mixer for 3 mins.
Add the egg and vanilla to combine.
Add the dry ingredients and mix until the dough is combined.
Weigh out 2.5 ounces of dough and roll into balls.
Bake for approx 12 mins. (Check at 10)-they should not be brown and will continue to bake as they cool on the hot sheet.
For smooth icing, frost when they have just a tad bit of warmth still and aren't completely cooled. If too hot, the frosting will melt.