Preheat oven to 350° F. Line two ungreased cookie sheets with parchment paper. Set aside.
In a medium mixing bowl, combine butter and sugar. Using an electric mixer on medium speed, cream the butter and sugar together until fluffy, about 2 minutes. Add the egg and vanilla and beat to incorporate. Scrape the bowl down and beat again. Add flour and salt and beat on low speed until incorporated.
To pipe cookies, place a #7 star tip (I used a 1M star tip, which might have been a little too small) in a pastry bag and pipe 2-inch cookies, leaving about an inch between cookies. Bake at 350° F for 10-12 minutes, until bottoms are light golden brown. Remove cookies to wire rack and allow to cool.