In a medium bowl, sift together flour and salt. Set aside.
In a mixer bowl place butter and sugar. With the mixer fitted with the paddle attachment, beat on medium-low speed for 2-3 minutes. Beat in vanilla extract. Reduce speed to low and add flour mixture, beating just until dough starts to come together. Do not overmix or the cookies will be tough.
Form dough into a ball, then flatten slightly to form a disc. Wrap with plastic wrap and refrigerate for 1-2 hours, until firm enough to roll. If you don’t want to use the dough right away, you can refrigerate it for up to 3 days or freeze it for up to a month, then thaw overnight in the fridge.
Take the dough out of the fridge and let it sit on the counter for a few minutes to soften slightly for easy rolling. On a lightly floured surface (or between 2 pieces of parchment paper), roll the dough to a ¼-inch thickness. Cut into 2-inch squares/rounds using a cookie cutter and place them on baking sheets lined with parchment paper. If at any point the dough becomes too warm, place it back into the fridge for a few minutes. Reroll the remaining scraps and repeat. Place sheets of cookies in the freezer or fridge for at least 15 minutes, until firm, so that they will be less prone to spreading.
Preheat oven to 350F/180C. Bake cookies for 8-12 minutes, or until cookies appear golden brown at the edges. Baking time will vary and may take longer depending on the size of your cookies. Allow cookies to cool in the pan for 10 minutes, then gently transfer to a wire rack to cool completely.
Place half of the chocolate in a heatproof bowl, then place the bowl over a saucepan of simmering water. Stir occasionally until melted. Add remaining chocolate and remove bowl from heat. Stir occasionally until smooth and glossy. Dip ½ of each cookie in the chocolate and place on a baking sheet lined with parchment paper. Place cookies in the refrigerator for a few minutes until chocolate hardens.
Store cookies at room temperature in an airtight container for up to a week.