Preheat oven to 350.Cream together the softened butter and sugar. Add the flour, salt and vanilla and mix until a soft dough comes together.
Wrap dough in plastic wrap and chill for thirty minutes.After chilling, roll dough into a log and gently slice 1/2-inch cookies. Place cookies on a lined cookie tray and bake for 10-12 minutes, or until the edges start to brown.Remove from oven and let cool completely.
To make the chocolate, pour the semisweet chips into a glass bowl and microwave for 30 seconds intervals until creamy and smooth, mixing well after each interval. Scoop warm melted chocolate into a small plastic bag and cut the tip off the bag. Drizzle the chocolate over each cookie and let cool to harden.