Preheat the oven to 350 degrees and prepare a baking sheet by lining with parchment paper. Set aside.

In a large bowl or stand mixer, mix the butter and sugar on medium low speed until light and fluffy.

Add the egg and vanilla and continue beating on medium low speed until smooth.

Slowly add the flour and salt just until fully incorporated – do not overmix.

Add the milk 1 tablespoon at a time, using the minimum amount possible to reach a piping consistency.

Place the batter in a piping bag, and pipe small circles onto the prepared baking sheet. Add sprinkles if desired. Chill the baking sheets in the refrigerator for at least 20-30 minutes.

Bake in the preheated oven for 10 minutes or until the edges of the cookies begin to turn golden brown.

Remove from the oven and cool completely before serving.