Preheat the oven to 180 degree Celsius. Line a muffin tin with paper liners. In a mixing bowl, sift together flour, baking powder and salt.
In a different bowl, add softened butter and using an electric hand mixer beat it for a minute.
Then add sugar and beat for about 2 to 3 minutes.
Add in the egg.
Beat well. Add the vanilla essence and whisk again.
Add a little flour mixture and fold it in.
Then add a little milk and fold again. Keep on adding flour mixture alternating with the milk.
Add the strawberries and chocolate raisins, gently fold it in. But do not overmix.
Pour the batter into the lined muffin tin and bake for about 25 minutes until its lightly golden. Using a toothpick pierce the centre of the muffins and if it comes out clean then it is done.
Take it out of the oven and keep it on a wire rack to cool down.
To make the buttercream frosting, using an electric hand mixer whip the butter until light and creamy for about 5 minutes.
Once the butter is pale yellow in colour, add the icing sugar one spoon at a time. Beat on low or medium speed. Once the sugar is fully incorporated, add in another spoon. Keep on repeating until all the sugar is added.
Add milk, vanilla essence and salt. Whip again for 5 minutes until light and fluffy.
Pour the buttercream frosting into a piping bag.
Pipe the frosting onto the cupcakes and garnish with strawberry slices.