Place the coffee granules in a small bag and crush with the back of a spoon to break up any large chunks.
In a In a medium sized bowl, cream the butter, sugar, instant coffee until light and fluffy. Scrape down the sides as necessary.
On low speed, mix in the egg and vanilla until well incorporated.
Add the salt and flour and continue mixing until the dough comes together.
Divide the dough in half and flatten into a disc. Wrap with plastic wrap and refrigerate for at least 2 hours (and up to overnight). Alternatively, pop it in the freezer for 20 minutes.
When ready to cut out the cookies, preheat the oven to 350°F.
Lightly flour your work surface (or a silicone mat) with flour, dust your rolling pin and very lightly dust the top of the cookie dough, before rolling it out to about ⅛ inch thick.
Cut with 2 ½ inch round cookie cutter (I like one with a fluted edge).
Transfer cookies to an unlined ungreased cookie sheet and bake for 10 – 12 minutes or until the edges just start to brown.
Immediately transfer to a wire rack to cool.
Store at room temperature for up to one week.