In a large bowl, cream the butter and sugar together (max. 1 minute). Beat in instant coffee and vanilla.
In a second bowl, sift together the flour and arrowroot powder. Add it to the butter mixture and mix together using your hands. Continue kneading it together until it forms a dough. (the mixture is quite dry at first and takes a few minutes to knead into a ball).
Mould the dough into a ball, cover with plastic wrap and refrigerate for 1 hour (or overnight).
Preheat the oven to 325°F / 165°C and line a baking sheet with parchment paper.
Mould the dough into the shape of coffee beans, using 2 teaspoons dough for each cookie.
Using the back of a knife, press a slight indent, lengthwise, across the top of each cookie (not too deep, otherwise the cookies will spread too much).
Transfer the cookies to the prepared baking sheet and bake in the preheated oven for 15 minutes. Remove and slide the parchment paper onto wire racks to cool the cookies.
Meanwhile, melt the chocolate in a double boiler. Dip one end of the cookies in the chocolate. Place on plates lined with parchment paper and refrigerate.
Once chocolate has hardened, serve and enjoy!
Be sure not to cream the butter too long as this will fill it with air bubbles which can result in the shortbread spreading too much while baking. It should be smooth, rather than fluffy.
I bake the cookies one batch at a time in the middle of the oven as this produces best results. Otherwise, it is important to rotate and switch places of the baking sheets to ensure two sheets of cookies bake evenly.
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