- Preheat oven to 175°Celsius. 
- Prepare cupcake liners. 
- In a small cup, dissolve instant coffee powder with hot water. Mix and set aside to cool. 
- In a separate bowl, cream the butter and sugar until light and fluffy. 
- Add the eggs, one at a time. Beat well after each addition. 
- Sift flour, baking powder and salt. Fold into the creamed mixture alternately with milk. Start and end with flour. 
- Finally, fold in the dissolved coffee and mix until the coffee is well distributed and the batter is evenly colored. 
- Scoop the batter into prepared cupcake casings and bake for approximately 20 minutes. The top of the cupcakes should spring back when lightly pressed. 
- Remove cupcakes from oven and let them cool down completely before frosting. 
- To make the coffee buttercream, dissolve the coffee in hot water. Set aside to cool. 
- In a medium-sized bowl, beat butter and shortening until soft and creamy. 
- Add in the sifted powdered sugar and beat until smooth. 
- Pour the coffee solution and continue to beat the buttercream until the coffee is evenly distributed in the buttercream. Add some milk or cream if the consistency is too stiff. 
- Fill the coffee buttercream into a piping bag fitted with a large star tip and pipe simple swirls on each cupcake. Top with a milk chocolate button.