Preheat oven to 180°C (350°F). Line a baking tray with baking paper.
Cream butter and sugar together until light and fluffy.
Add vanilla essence and egg, mix well.
Dissolve coffee granules in 1 tbsp hot water and add to mixture.
Sift in flour, baking powder, and salt. Mix to form a soft dough.
Roll into small balls (about 2–3 cm) and place on tray, spacing 2 cm apart.
Flatten slightly with the back of a fork or glass.
Bake for 12–15 minutes until lightly golden at the edges.
Cool on a wire rack and optionally dust with icing sugar.