Preheat oven to 170°Celsius. Prepare cupcake liners.
Beat butter and sugar until light and fluffy, for approximately 3 minutes. Scrape the sides of the bowl constantly.
Add the eggs, one at a time, beating well after each addition.
Sift in the flour, baking powder and salt into the creamed mixture in 4 batches, alternating each batch with milk. Start and end with the flour. Mix until the flour is well incorporated.
Fold in the vanilla essence followed by the sprinkles.
Pour batter into prepared cupcake liners and bake for 20 minutes until the cupcakes are well risen and have turned golden brown.
Remove the cupcakes from the oven and let them cool in the tin for 5 minutes before removing them onto a wire rack to cool further.
Keep the cupcakes covered as soon as they turn warm and let them continue to cool down, covered.
To make the buttercream, cream the butter until fluffy. Sift in the icing sugar, a little at a time.
Add vanilla and continue beating until the buttercream is light and fluffy. Add milk if it is too stiff.
Frost the cupcakes only when they have completely cooled down. Fill buttercream into a piping bag fitted with a large star tip and pipe a star on top of each cupcake. Decorate with sprinkles and attach a red fondant star in the center.