In a medium sized mixing bowl, combine the flour, baking soda, baking powder, and salt with a whisk, then set aside.

In a large mixing bowl, add softened butter and granulated sugar. Cream them together with an electric mixer until light and fluffy. Add in the egg, and mix until combined. Then add in the vanilla and milk, mixing until everything is well combined.

Add the dry ingredients into the wet ingredients gradually, mixing well between each addition. Scrape down the sides of the mixing bowl when needed.

Use a cookie scoop to scoop 1 ½ tablespoon portions of dough onto a parchment lined baking sheet. They can be close together, but not touching. Cover the tray with plastic wrap and chill for at least two hours, and up to overnight.

Line two sheet trays with a Silpat or parchment paper and preheat the oven to 375°F/190°C. Pour the decorator’s sugar into a small bowl, and remove the dough from the fridge.

Roll each cookie ball between your palms to form a smooth ball. Dip the tops of the balls into the decorator’s sugar, and place them sugar side up on prepared cookie sheets. Keep them 2 inches apart to allow for spreading.

Bake for 8-11 minutes until lightly golden brown around the edges. Let the cookies cool on the tray for 10 minutes, then transfer to a wire cooling rack.