Begin by dissolving 1 tablespoon of instant coffee in 2 tablespoons of hot water in a small bowl. Stir until fully dissolved, then set aside to cool slightly.

In a large mixing bowl, beat 1 stick of softened unsalted butter and 1 cup of icing sugar using an electric mixer on medium speed until light and fluffy, about 3-4 minutes.

Add 1 large beaten egg to the creamed butter and sugar mixture. Mix on low speed until fully combined.

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

Slowly fold the cooled coffee mixture into the creamed butter and egg mixture until thoroughly blended. Gradually add the dry ingredients, mixing gently until just combined.

Transfer the cookie dough into a piping bag fitted with a large star or round tip. On a lined baking tray, pipe rounds or shapes of dough.

Place the piped dough in the freezer for 5-10 minutes to help maintain their shape.

Preheat your oven to 350°F (175°C). Bake the cookies in the center of the oven for about 8 minutes, until the edges are lightly golden.

Once the cookies are cooled, dip the edges in melted dark chocolate and sprinkle with chopped pistachios. Allow the chocolate to set before serving.