Preheat your oven to 175°C (350°F) and line a muffin tin with paper liners.
Sift together the flour, cocoa powder, baking soda, and salt in a large bowl until well combined and light.
In a separate bowl, beat the softened butter and sugar with an electric mixer on medium speed until the mixture is pale, fluffy, and fragrant, about 3-4 minutes.
Add eggs one at a time, beating well after each addition, then stir in vanilla extract until evenly incorporated.
Alternately add the first half of the buttermilk and the dry ingredients to the butter mixture, starting and ending with the dry, mixing just until each addition is combined.
Pour in the remaining buttermilk and gently fold until the batter is smooth, glossy, and free of lumps.
Divide the batter evenly among the cupcake liners, filling each about two-thirds full.
Bake for 18-20 minutes, until the tops are domed and slightly cracked, and a toothpick inserted into the center comes out clean.
Remove the cupcakes from the oven and let them cool in the tin for 5 minutes before transferring to a wire rack to cool completely.
Once cooled, frost the cupcakes with your favorite dark chocolate or cream cheese frosting for a decadent finish.
