Prepare the Batter
In a mixing bowl, beat the softened butter until creamy.
Add the condensed milk and mix well.
Beat in the eggs one at a time until fully incorporated.
Mix the Dry Ingredients
In a separate bowl, sift together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until smooth.
If using, fold in the raisins.
Bake the Cupcakes
Preheat the oven to 180°C (350°F).
Line a muffin tin with cupcake liners and fill each about ¾ full with batter.
Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Cool and Serve
Let the cupcakes cool completely before adding toppings.
Dust with powdered sugar or drizzle with melted chocolate for extra flavor.