Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a large bowl, cream together butter and sugar until light and fluffy.
Add eggs one at a time, then mix in vanilla extract.
In a separate bowl, whisk together flour, baking powder, and salt.
Gradually mix dry ingredients into wet ingredients, alternating with milk.
Gently fold in diced strawberries and mango.
Fill each cupcake liner 2/3 full with the batter.
Bake for 18–22 minutes or until a toothpick inserted comes out clean.
Let cupcakes cool completely on a wire rack before frosting.
To make the frosting, beat butter until smooth, then gradually add powdered sugar.
Add heavy cream and vanilla, and mix until fluffy. Blend in fruit puree if desired.
Frost cooled cupcakes and garnish with extra fruit if desired.