Preheat the oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.

In a large mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the milk, and mix until just combined.

Gently fold in the diced strawberries and mango.

Divide the batter evenly among the cupcake liners, filling each about two-thirds full.

Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.

For the frosting, beat together the powdered sugar, 2 tablespoons of milk, and 1 teaspoon of vanilla extract until smooth and creamy.

Once the cupcakes are completely cool, frost them with the prepared frosting.