Preheat your oven to 350°F (175°C) and line a cupcake tin with liners.
In a mixing bowl, whisk together the flour, cocoa powder, sugar, baking powder, baking soda, and salt.
Add the milk, vegetable oil, vanilla extract, and egg. Mix until smooth.
Divide the batter evenly among the cupcake liners, filling each about ⅔ full.
Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean. Let cool completely.
For the frosting, beat the softened butter until creamy. Gradually add the powdered sugar, raspberry puree, and vanilla extract. Beat until smooth and fluffy.
Once the cupcakes are cool, frost them using a piping bag or a knife.