Cream butter and sugar on medium speed until fluffy.
Add egg, vanilla, and salt; mix until smooth.
Gradually blend in flour and chill for 30 minutes.
Roll dough, cut circles, and remove centers; chill again.
Bake at 350°F for 12 minutes; cool completely.
Melt chocolate; dip cookie bottoms and drizzle tops. Chill for 10 minutes.
