Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a mixing bowl, sift together the flour, cocoa powder, baking powder, baking soda, and salt.
In another bowl, cream the butter and granulated sugar until light and fluffy, about 3-4 minutes.
Add the eggs one at a time, mixing well after each addition, then stir in the vanilla.
Alternate adding the dry ingredients and buttermilk to the butter mixture, starting and ending with the dry ingredients.
Gently fold in the fresh raspberries to the cupcake batter.
Divide the batter evenly among the prepared cupcake liners, filling each about two-thirds full.
Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean.
Remove from the oven and let cool in the tin for 5 minutes before transferring to a wire rack to cool completely.
While the cupcakes cool, prepare the frosting by beating the butter until creamy, then gradually add the powdered sugar and cocoa powder.
Mix in the raspberry puree until well combined and smooth, adjusting consistency with milk if necessary.
Frost the cooled cupcakes generously with the raspberry chocolate frosting, then garnish with additional raspberries if desired.
