Dissolve 1 tablespoon of instant coffee in 2 tablespoons of hot water, stirring until fully dissolved. Allow to cool.

In a large mixing bowl, beat 1 stick of softened unsalted butter with 1 cup of icing sugar until light and fluffy, about 3-5 minutes.

Add 1 large beaten egg to the mixture and mix on low speed until smooth.

In a separate bowl, whisk together 2 cups of all-purpose flour, 1 tablespoon of cornstarch, and 1 teaspoon of ground cinnamon.

Fold the cooled coffee mixture into the butter and egg mixture, then gradually add the dry ingredients, mixing until just combined.

Pipe the dough onto a lined baking tray, keeping them about an inch apart.

Freeze the piped cookies for 5 to 10 minutes.

Preheat your oven to 350°F (175°C) while the dough chills. Bake for approximately 8 minutes or until lightly golden.

Once cooled, dip the edges of cookies into melted dark chocolate and sprinkle with chopped pistachios.