Mix the instant coffee granules (3 tbsp) with the boiling water (1½ tbsp) and then set aside to cool.
Cut the butter (250g) into cubes and then beat on a low-medium speed until soft. Gradually add the icing sugar (you add it gradually to stop it flying everywhere) and beat until fully combined.
Add the vanilla extract (¼tsp) and add the coffee a teaspoon at a time, beating in each addition before adding more.
Check the consistency of your buttercream. It should be soft and perfect for piping at this point. If it’s still a little stiff then beat in a little milk.
Decorate your cakes (or just eat if off the spoon because it’s yummy!).
Calories: 316kcal | Carbohydrates: 42g | Fat: 16g | Saturated Fat: 10g | Cholesterol: 44mg | Sodium: 150mg | Potassium: 49mg | Sugar: 40g | Vitamin A: 520IU | Calcium: 7mg | Iron: 0.1mg
Any nutritional information provided is the estimated nutritional information per serving. Please refer to my guide to Charlotte’s Lively Kitchen nutritional information if you would like to learn more about how this is calculated.